Slow Rotation of the Earth
Centrifual force exactly as a sphere predicts
Weighing more at equator
Earth is an inertial reference frame
Slow spin not fast, so perfectly works (angular speed vs tangential speed)
Bogus vortex model and relative speeds
Orbital spin explains seasons and why they are as long as they are
Orbital inclination and why we do not see eclipses every month
Keplers laws exact predict orbiting earth trajectory, change of speeds, etc.
Cyclonic Rotation: The Direction a Cyclone or Hurricane Rotates
Centrifual force exactly as a sphere predicts
Weighing more at equator
Earth is an inertial reference frame
Slow spin not fast, so perfectly works (angular speed vs tangential speed)
Bogus vortex model and relative speeds
Orbital spin explains seasons and why they are as long as they are
Orbital inclination and why we do not see eclipses every month
Keplers laws exact predict orbiting earth trajectory, change of speeds, etc.
Cyclonic Rotation: The Direction a Cyclone or Hurricane Rotates
An inertial system is a frame of reference in which the law of inertia  Newton's first law  holds. In such a system which also may be described as an unaccelerated system, a body that is acted on by zero net external force will move with a constant velocity.
In practice we can often neglect the small (accleration) effects dues to the rotation and orbital motion of the earth.
**You Cannot Locally Measure Speed. You can measure acceleration. You can measure your speed relative to something else. But there is NO instrument that can say "you are going 20 mph". It's always relative to something else. Prove me wrong  devise a mechanism that will measure SPEED directly and locally without reference to anything outside the vehicle. You will be a millionaire because nobody else in the world has ever done this.

Prove me wrong  show me an electronic device that measures speed while being completely enclosed with no input from the outside world  no radio signals, no opticals, just measures it locally.

In a car, your speedometer measures the rotation of the axle  it literally counts how many times it goes around per unit time and guesses a speed based on that given the standard tire size for that vehicle. Change your tire size and it will read out incorrectly.
People on the Concorde going 1341 mph could walk up and the down aisles freely because you do not feel speed. They could juggle, pour water, stand, walk, all with no problem. The only time it's a problem is when it isn't smooth because that causes many sharp accelerations in all directions.
The rotation of the Earth is slowing down by about 1.8 milliseconds per Century right now (this slowdown is not uniform over all time, so you cannot extrapolate it naively).

We feel stationary
We are all moving with the earth. It has never changed its speed.
Only when speed changes do you feel movement.
You feel stationary
Only when you change your speed do you become aware of the fact that your are moving.
This is one of the most fundamental laws of physics, that when you are moving at a constant speed you are not aware of that movement.
Only if the earths rotation or orbit suddenly speeded up would we be aware of that movement.
Think of a car.
When we stick our head out of a window in a car, we feel the air rush past us.
So when the earth is rotating with a tangential speed of 1000 mph, why don't we feel it?
Well it is because the earth's atmosphere is held there by gravity.
So how do we know the earth is moving then? Well just a car, you can see objects moving past you and infer you are moving. We look at the sun and stars.
In practice we can often neglect the small (accleration) effects dues to the rotation and orbital motion of the earth.
**You Cannot Locally Measure Speed. You can measure acceleration. You can measure your speed relative to something else. But there is NO instrument that can say "you are going 20 mph". It's always relative to something else. Prove me wrong  devise a mechanism that will measure SPEED directly and locally without reference to anything outside the vehicle. You will be a millionaire because nobody else in the world has ever done this.

Prove me wrong  show me an electronic device that measures speed while being completely enclosed with no input from the outside world  no radio signals, no opticals, just measures it locally.

In a car, your speedometer measures the rotation of the axle  it literally counts how many times it goes around per unit time and guesses a speed based on that given the standard tire size for that vehicle. Change your tire size and it will read out incorrectly.
People on the Concorde going 1341 mph could walk up and the down aisles freely because you do not feel speed. They could juggle, pour water, stand, walk, all with no problem. The only time it's a problem is when it isn't smooth because that causes many sharp accelerations in all directions.
The rotation of the Earth is slowing down by about 1.8 milliseconds per Century right now (this slowdown is not uniform over all time, so you cannot extrapolate it naively).

We feel stationary
We are all moving with the earth. It has never changed its speed.
Only when speed changes do you feel movement.
You feel stationary
Only when you change your speed do you become aware of the fact that your are moving.
This is one of the most fundamental laws of physics, that when you are moving at a constant speed you are not aware of that movement.
Only if the earths rotation or orbit suddenly speeded up would we be aware of that movement.
Think of a car.
When we stick our head out of a window in a car, we feel the air rush past us.
So when the earth is rotating with a tangential speed of 1000 mph, why don't we feel it?
Well it is because the earth's atmosphere is held there by gravity.
So how do we know the earth is moving then? Well just a car, you can see objects moving past you and infer you are moving. We look at the sun and stars.
You cannot locally measure or feel speed alone. No instrument exists which measures speed but in relation to the motion of some other object. The speedometer in your car measures the rotational rate of a wire coming from the axle and assumes the size of the tires to estimate speed  your odometer will be incorrect over time if you change the size of your tires.
In a car, on a train, or on a plane  what you feel are the little accelerations on the moving vehicle as bumps and twists that give you the sensation of speed but if you were isolated inside a box you couldn't tell you were actually moving.
All these high speeds are our relative speeds to other objects in the Universe.
In a car, on a train, or on a plane  what you feel are the little accelerations on the moving vehicle as bumps and twists that give you the sensation of speed but if you were isolated inside a box you couldn't tell you were actually moving.
All these high speeds are our relative speeds to other objects in the Universe.
"I have never felt the Earth spinning beneath me at 1,000 mph"
That's because you cannot feel, sense, or in any way detect speed using a local measurement. We measure speed relative to something else. Your GPS measures speed by looking at your positional changes over time, that information comes by comparing transmitted time signatures. It isn't a local measurement.
The Concorde could cruise at 1,354 mph but nobody had a problem getting up and walking up and down the isles. This is another flat Earth claim that is just facile.
We've computed the centrifugal acceleration of the Earth's rotation and found it is tiny compared to the force of Gravity and since it is a constant acceleration it merely cancels out that 0.3% portion of Gravity so we feel slightly lighter at the Equator than the Poles (not enough to be able to feel a difference but measurably so).
That's because you cannot feel, sense, or in any way detect speed using a local measurement. We measure speed relative to something else. Your GPS measures speed by looking at your positional changes over time, that information comes by comparing transmitted time signatures. It isn't a local measurement.
The Concorde could cruise at 1,354 mph but nobody had a problem getting up and walking up and down the isles. This is another flat Earth claim that is just facile.
We've computed the centrifugal acceleration of the Earth's rotation and found it is tiny compared to the force of Gravity and since it is a constant acceleration it merely cancels out that 0.3% portion of Gravity so we feel slightly lighter at the Equator than the Poles (not enough to be able to feel a difference but measurably so).
Scale and Curvature Matters
But on your second point on why don't we have an accelerometer to measure earth's linear speed. You are not quite understanding acceleration, which is ok, because without physics training this is not obvious. Unlike some debunkers I really am trying to teach not belittle, so I like questions like this.
Constant linear speeds have no acceleration because acceleration requires a change in velocity, hence why accelerometers cannot be measure linear constant speed. Below is an image of a bullet train traveling at a constant speed of 300 km/hr. Now if the train suddenly sped up or slowed down, then all these objects would topple over and an accelerometer would measure this, but not at constant speed. It turns out the earth's rotation is nearly perfectly constant.
Here is the thing, while the tangential speed of the earth is not exactly in a straight line, it will have a little centrifugal acceleration, but it is a very small curvature (huge earth) relative to our scale (small people). This term in math curvature quantifies how sharp a path or object is curved (also can be defined by its inverse, the radius of curvature). This value can go from 0 (straight line no curvature) to 1 (point with infinite curvature). Can you see that if you make a circle bigger and bigger and bigger the curve flattens out to approximate a straight line (I will share an image on this below). So because of this, the earths centrifugal acceleration is small because the earth is so large (again this is related to the potential energy/Force vs R graph I showed). Curvature matters. Radius matters. Speed matters less, but is significant for small R. Speed can also be significant for big R, but would have to be ridiculously fast. This is why we have to do science, to see exactly how it all fits together. And when you put it together, it is obvious that the rim velocity of 1040 miles per hour at the equator is not fast enough for a huge sphere of radius 3950 miles. It is hard to see this UNLESS you do the math. Again science matters! Math matters!
But on your second point on why don't we have an accelerometer to measure earth's linear speed. You are not quite understanding acceleration, which is ok, because without physics training this is not obvious. Unlike some debunkers I really am trying to teach not belittle, so I like questions like this.
Constant linear speeds have no acceleration because acceleration requires a change in velocity, hence why accelerometers cannot be measure linear constant speed. Below is an image of a bullet train traveling at a constant speed of 300 km/hr. Now if the train suddenly sped up or slowed down, then all these objects would topple over and an accelerometer would measure this, but not at constant speed. It turns out the earth's rotation is nearly perfectly constant.
Here is the thing, while the tangential speed of the earth is not exactly in a straight line, it will have a little centrifugal acceleration, but it is a very small curvature (huge earth) relative to our scale (small people). This term in math curvature quantifies how sharp a path or object is curved (also can be defined by its inverse, the radius of curvature). This value can go from 0 (straight line no curvature) to 1 (point with infinite curvature). Can you see that if you make a circle bigger and bigger and bigger the curve flattens out to approximate a straight line (I will share an image on this below). So because of this, the earths centrifugal acceleration is small because the earth is so large (again this is related to the potential energy/Force vs R graph I showed). Curvature matters. Radius matters. Speed matters less, but is significant for small R. Speed can also be significant for big R, but would have to be ridiculously fast. This is why we have to do science, to see exactly how it all fits together. And when you put it together, it is obvious that the rim velocity of 1040 miles per hour at the equator is not fast enough for a huge sphere of radius 3950 miles. It is hard to see this UNLESS you do the math. Again science matters! Math matters!
The funny thing is you CAN actually get water to stick to a spinning ball.
Spin at a rate to give .03 m/s^2 acceleration. use v^2/r = .03
Apparently, if you have a sufficient force, water CAN cling to things, even if they are spinning. Maybe, since the acceleration of gravity is about 9.807m/s² and the centrifugal acceleration of the Earth is rω² = ~0.0339... m/s²  the spinning counteracts only a tiny fraction of the centripetal acceleration of gravity so there is no NET outward force. How about that…
You can actually get water to stick to a small ball (smooth stone shown here) due to adhesion forces.
You can do a similar test yourself. And if you want to do it to scale, that equates to almost exactly two drops of a water on a rock the size of a billiard cueball (I actually did the math). The water of the earth is 1/1000 the volume of the whole earth. Shown here is a rock spinning proportionately faster than the earth with proportionately more water. Still no problem! So considered this debunked.
Oh and in zero gravity water aggregates to a sphere. So actually that is its natural shape with no external forces acting!
Spin at a rate to give .03 m/s^2 acceleration. use v^2/r = .03
Apparently, if you have a sufficient force, water CAN cling to things, even if they are spinning. Maybe, since the acceleration of gravity is about 9.807m/s² and the centrifugal acceleration of the Earth is rω² = ~0.0339... m/s²  the spinning counteracts only a tiny fraction of the centripetal acceleration of gravity so there is no NET outward force. How about that…
You can actually get water to stick to a small ball (smooth stone shown here) due to adhesion forces.
You can do a similar test yourself. And if you want to do it to scale, that equates to almost exactly two drops of a water on a rock the size of a billiard cueball (I actually did the math). The water of the earth is 1/1000 the volume of the whole earth. Shown here is a rock spinning proportionately faster than the earth with proportionately more water. Still no problem! So considered this debunked.
Oh and in zero gravity water aggregates to a sphere. So actually that is its natural shape with no external forces acting!
Centrifugal Force
First of all, there is no such force as centrifugal force! It is an apparent force that acts outward on a body that is being accelerated, but it actually arises from the inertia of mass. It is EXACTLY the same apparent force that 'throws you forward' when you slam on the breaks in your car  but when the body in question is rotating we call it centrifugal force.
Newton's first law of motion (the Law of Inertia): An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
So the centrifugal acceleration is really just due to inertia.
==>What is a Force? Force is the mass multiplied by the acceleration  for the remainder of this discussion we will focus on the acceleration component rather than the force.
So what is the effective/apparent centrifugal acceleration at Earth's equator?
If the centrifugal acceleration is greater than the acceleration due to gravity then the thing would fly off.
And it turns out we can figure out the centrifugal acceleration very easily if we just know the radius around which we are rotating and something called our angular velocity.
If we were standing on the equator then our distance from the center of Earth's rotation would be 6,378,137 meters (or 3,959 miles  NOTE: the distance to the north pole is a mere 9.1 miles difference), and we know our rotational rate is once every 24 hours.
So let's define our values:
T = 86164.09054 seconds (time, 1 sidereal day)
ω = 2π/T (angular velocity  simply the angle we turn divided by the time, 2π radians = 360°)
r = 6378137 meters (equatorial radius of Earth)
And finally centrifugal acceleration simply equals the radius times the angular velocity squared.
centrifugal acceleration = rω² = 0.0339... m/s²
So it turns out our centrifugal acceleration is a mere ~0.0339 m/s² which is working against the acceleration of Gravity which was 9.807 m/s²
Gravity is 289 times STRONGER than the centrifugal acceleration.
You can also do this based on the velocity at the equator (1040 mph = 464.9216 m/s)
v²/r = (464.9216 m/s)²/(6378137 m) = 0.0338895345 m/s²
So we can safely say that you would NOT fly off the Earth because of this rate of rotation.
First of all, there is no such force as centrifugal force! It is an apparent force that acts outward on a body that is being accelerated, but it actually arises from the inertia of mass. It is EXACTLY the same apparent force that 'throws you forward' when you slam on the breaks in your car  but when the body in question is rotating we call it centrifugal force.
Newton's first law of motion (the Law of Inertia): An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
So the centrifugal acceleration is really just due to inertia.
==>What is a Force? Force is the mass multiplied by the acceleration  for the remainder of this discussion we will focus on the acceleration component rather than the force.
So what is the effective/apparent centrifugal acceleration at Earth's equator?
If the centrifugal acceleration is greater than the acceleration due to gravity then the thing would fly off.
And it turns out we can figure out the centrifugal acceleration very easily if we just know the radius around which we are rotating and something called our angular velocity.
If we were standing on the equator then our distance from the center of Earth's rotation would be 6,378,137 meters (or 3,959 miles  NOTE: the distance to the north pole is a mere 9.1 miles difference), and we know our rotational rate is once every 24 hours.
So let's define our values:
T = 86164.09054 seconds (time, 1 sidereal day)
ω = 2π/T (angular velocity  simply the angle we turn divided by the time, 2π radians = 360°)
r = 6378137 meters (equatorial radius of Earth)
And finally centrifugal acceleration simply equals the radius times the angular velocity squared.
centrifugal acceleration = rω² = 0.0339... m/s²
So it turns out our centrifugal acceleration is a mere ~0.0339 m/s² which is working against the acceleration of Gravity which was 9.807 m/s²
Gravity is 289 times STRONGER than the centrifugal acceleration.
You can also do this based on the velocity at the equator (1040 mph = 464.9216 m/s)
v²/r = (464.9216 m/s)²/(6378137 m) = 0.0338895345 m/s²
So we can safely say that you would NOT fly off the Earth because of this rate of rotation.
How to make a merry go round create the same centrifugal acceleration as earth.
We remember being on the playground merrygoround and being thrown off that and it wasn't going anywhere NEAR 1040 miles per hour!
So why is our intuition about this so wrong? The answer again lies in understanding inertia.
Let's use the same math from above to work out the acceleration for our little merrygoround where we are hanging on to the outer edge (about 5 feet or 1.524 meters from our center of rotation as that is a 10 foot merrygoround) and assume we're a 50 kg kid.
What if we SLOWLY walked the merrygoaround taking, oh say, 42.1282 seconds to go all the way around once (just to pick a random number)?
42.1282s = 0.0339 m/s²
Hey! That's the SAME acceleration as Earth spinning at 1040 miles per hour! Let's see  radius of 1.524 meters = circumference 9.576 meters around... that's only 1/2 mile per hour  that's a SLOW walk around.
We remember being on the playground merrygoround and being thrown off that and it wasn't going anywhere NEAR 1040 miles per hour!
So why is our intuition about this so wrong? The answer again lies in understanding inertia.
Let's use the same math from above to work out the acceleration for our little merrygoround where we are hanging on to the outer edge (about 5 feet or 1.524 meters from our center of rotation as that is a 10 foot merrygoround) and assume we're a 50 kg kid.
What if we SLOWLY walked the merrygoaround taking, oh say, 42.1282 seconds to go all the way around once (just to pick a random number)?
42.1282s = 0.0339 m/s²
Hey! That's the SAME acceleration as Earth spinning at 1040 miles per hour! Let's see  radius of 1.524 meters = circumference 9.576 meters around... that's only 1/2 mile per hour  that's a SLOW walk around.
What is going on here?
Both the merrygoround and the Earth are TRYING to give us the slip  but the Earth has a HUGE radius so even at 1040 miles per hour FORWARD (or 0.288 miles per second) and we know from the drop rate equation (8 inches times miles squared) that the drop over 1 second is about 2 inches per second or just ~0.05 m/s! Meanwhile, Gravity is sucking you down at 9.807 m/s² and since both accelerations are constant.
So it really has to do with how fast the 'thing' is moving 'out from under you' NOT merely how fast around you are going  the distance from the center of rotation has as much to do with it as the raw speed.
You can also try thinking about your experience in a car. Even when traveling fairly slowly, if the car takes a sharp turn you are thrown to the side with a moderate amount of force. But in a very fast moving car, moving around a larger curve of the freeway you feel much less force than the slower car turning abruptly  despite going even 10 times faster. So the size of this curve matters a lot and the curvature of the Earth is enormous, 1000 times flatter than the curve in the road.
Spin It Faster!
What happens if we spin our kids ten times faster, or once around every 4.2128 seconds?
4.2128 = 3.39 m/s² [Wolframalpha]  no surprise, we just went 10 x faster and got 10 x the acceleration.
And if we convert that to the force felt by a 50 kg kid we get 169.5 Newtons or about 38 pounds of force pushing our kid sideways.
That's pretty accurate.
Both the merrygoround and the Earth are TRYING to give us the slip  but the Earth has a HUGE radius so even at 1040 miles per hour FORWARD (or 0.288 miles per second) and we know from the drop rate equation (8 inches times miles squared) that the drop over 1 second is about 2 inches per second or just ~0.05 m/s! Meanwhile, Gravity is sucking you down at 9.807 m/s² and since both accelerations are constant.
So it really has to do with how fast the 'thing' is moving 'out from under you' NOT merely how fast around you are going  the distance from the center of rotation has as much to do with it as the raw speed.
You can also try thinking about your experience in a car. Even when traveling fairly slowly, if the car takes a sharp turn you are thrown to the side with a moderate amount of force. But in a very fast moving car, moving around a larger curve of the freeway you feel much less force than the slower car turning abruptly  despite going even 10 times faster. So the size of this curve matters a lot and the curvature of the Earth is enormous, 1000 times flatter than the curve in the road.
Spin It Faster!
What happens if we spin our kids ten times faster, or once around every 4.2128 seconds?
4.2128 = 3.39 m/s² [Wolframalpha]  no surprise, we just went 10 x faster and got 10 x the acceleration.
And if we convert that to the force felt by a 50 kg kid we get 169.5 Newtons or about 38 pounds of force pushing our kid sideways.
That's pretty accurate.
Also, the figures stated are our relative speeds to other objects in the Universe.
Chinese bullet train traveling well over 200 mph!
Flat earthers, when are you going to realize spin is NOT measure in miles per hour, it is measure in radians per second, revolutions per minute (rpms), cycles per second, etc.
NOT miles per hour. We do not feel speed, we feel acceleration and the rotation of the earth is twice as slow as the hour hand on your watch. You do realize that right? Once every 24 hours it rotations? That is incredibly slow. Get on a merry go round and have someone spin you a speed 1/2 as slow as the hour hand on your clock?
Now the earth is huge so this translates into large linear speeds at the equation, but linear speed creates no force.
What DOES create a force is the circular motion, which can be measured as the Centrifugal force. This turns out to be only .003 m/s^2 which is 1/300 the accleration of gravity and literally below our biological perception to feel it!
Look at this bullet train going 300 km/hr or 170 miles per hour. There is next to zero force because the train is moving constant speed.
When are you flat earth believers going to get through your skull that you cannot feel speed or velocity, you only FEEL ACCELERATION (like if this train speeded up or stopped suddenly)!
Flat earthers, when are you going to realize spin is NOT measure in miles per hour, it is measure in radians per second, revolutions per minute (rpms), cycles per second, etc.
NOT miles per hour. We do not feel speed, we feel acceleration and the rotation of the earth is twice as slow as the hour hand on your watch. You do realize that right? Once every 24 hours it rotations? That is incredibly slow. Get on a merry go round and have someone spin you a speed 1/2 as slow as the hour hand on your clock?
Now the earth is huge so this translates into large linear speeds at the equation, but linear speed creates no force.
What DOES create a force is the circular motion, which can be measured as the Centrifugal force. This turns out to be only .003 m/s^2 which is 1/300 the accleration of gravity and literally below our biological perception to feel it!
Look at this bullet train going 300 km/hr or 170 miles per hour. There is next to zero force because the train is moving constant speed.
When are you flat earth believers going to get through your skull that you cannot feel speed or velocity, you only FEEL ACCELERATION (like if this train speeded up or stopped suddenly)!
A Deeper Look Rim Velocity vs Acceleration (Which is more important?)
We all know flat earth enthusiasts love to throw out big numbers, 1040 mph, 67,000 mph, 500,000 mph, etc. These are the tangential speeds of the earths rotation at the equator, the average earth orbital speed around the sun, and the suns orbital speed around the equator. It is popular for the flat earth community to call these "rim velocities" and they claim they are what is most important. Well, lets look at that.
I used to teach college physics and I have written a lot about this. It is not easy, but you can rewrite Newtons laws for a noninertial reference frames like the rotating earth and calculate the total net forces acting on objects in this rotating frame. There are essentially 4 terms, the downward force of gravity, the radially outward centrifugal force, and the Coriolis force (which has two components one being Eotvos force). The Euler force is not relevant.
It boils down to that we do not feel speed, we feel acceleration/force and for rotating systems there is an equation where you can plot the total net energy or force (inward gravitational force vs outward centrifugal force) vs the radius (R). It turns out for small R, the outward centrifugal term dominates (like what a tire technician will see because the radius is small and it is spinning fast and has very little mass). I think this is why the term rim velocity is getting used, but you cannot compare a fast spinning tire to a slow rotating earth, even if the earth has high tangential speeds (or rim velocity). For a large R, the gravitational term dominations (or whatever the inward centripetal force is operating in the rotating system).
Here is where science matters. From the graph of net Force vs Radius (R), when R is LARGE like the earth, the the inward force of Gravity dominates because the earth is 6 sextillion tons and the radius R is huge (3950 miles). When R is small , like a tire, the centrifugal force dominates and things would spin off (water, etc).
And you can calculate this outward centrifugal force on the earth (what we feel and what is "spinning us off") as only .03 m/s^2 times the mass of the object while the gravitational force at the equator is a little over 9.8 m/s^2 times the mass of the object.
THE NET FORCE is Fg  Fc (where Fg is the gravitational Force) 9.8  .03 which is obvious not much of a change ~9.77. This is why , btw, we weight LESS at the equator than the poles (another excellent proof the earth is rotating and why they use counter balance scales to weigh gold instead of traditional scales otherwise people could buy gold in Ecuador and sell in Alaska and make a profit).
So you can see why science and quantification matters, which flat earth enthusiasts (in general) seem to ignore or avoid. You can't just say rim velocity while ignoring that the acceleration due to this velocity is minuscule for large R.
And FYI, these numbers get smaller and smaller for orbits around sun, galaxy and local cluster BECAUSE R gets larger exponentially more than the speeds do. Again this is the right answer, but flat earth enthusiasts seem to deny science at their own parole.
Note: U on the attached graph is the potential energy, which is just the Force rewritten for easier calculations because it is easier to manage scalars vs vectors. But because force is just the () gradient of the potential, these relationships hold perfect. So energy and force are essentially going to have the same relationship here in this graph.
**Note: this is a center of mass two body problem. If you take your body to be the second mass sitting down. You will be rotating in a circular orbit (speed and radius depends on your latitude) around the combined center of mass. The center of mass will be the earth's center of mass because your mass is so small.
==> key point to debunk flat earth proponents:
So to "spin you off", the centrifugal force will have to be GREATER than gravity. If you lived at the equator which is the place you will "spin off" first, the earth's centrifugal acceleration has to be greater than 9.8 meters per second^2. To calculate the speed needed with the earth's known radius, use the equation for centrifugal acceleration v^2/R = 9.8, solve for v and you get a rim velocity of 17,689.69 miles per hour!
And guess what? That is the known escape velocity of the earth (how fast rockets have to go to escape the earth's gravity well)! How cool is that!!
We all know flat earth enthusiasts love to throw out big numbers, 1040 mph, 67,000 mph, 500,000 mph, etc. These are the tangential speeds of the earths rotation at the equator, the average earth orbital speed around the sun, and the suns orbital speed around the equator. It is popular for the flat earth community to call these "rim velocities" and they claim they are what is most important. Well, lets look at that.
I used to teach college physics and I have written a lot about this. It is not easy, but you can rewrite Newtons laws for a noninertial reference frames like the rotating earth and calculate the total net forces acting on objects in this rotating frame. There are essentially 4 terms, the downward force of gravity, the radially outward centrifugal force, and the Coriolis force (which has two components one being Eotvos force). The Euler force is not relevant.
It boils down to that we do not feel speed, we feel acceleration/force and for rotating systems there is an equation where you can plot the total net energy or force (inward gravitational force vs outward centrifugal force) vs the radius (R). It turns out for small R, the outward centrifugal term dominates (like what a tire technician will see because the radius is small and it is spinning fast and has very little mass). I think this is why the term rim velocity is getting used, but you cannot compare a fast spinning tire to a slow rotating earth, even if the earth has high tangential speeds (or rim velocity). For a large R, the gravitational term dominations (or whatever the inward centripetal force is operating in the rotating system).
Here is where science matters. From the graph of net Force vs Radius (R), when R is LARGE like the earth, the the inward force of Gravity dominates because the earth is 6 sextillion tons and the radius R is huge (3950 miles). When R is small , like a tire, the centrifugal force dominates and things would spin off (water, etc).
And you can calculate this outward centrifugal force on the earth (what we feel and what is "spinning us off") as only .03 m/s^2 times the mass of the object while the gravitational force at the equator is a little over 9.8 m/s^2 times the mass of the object.
THE NET FORCE is Fg  Fc (where Fg is the gravitational Force) 9.8  .03 which is obvious not much of a change ~9.77. This is why , btw, we weight LESS at the equator than the poles (another excellent proof the earth is rotating and why they use counter balance scales to weigh gold instead of traditional scales otherwise people could buy gold in Ecuador and sell in Alaska and make a profit).
So you can see why science and quantification matters, which flat earth enthusiasts (in general) seem to ignore or avoid. You can't just say rim velocity while ignoring that the acceleration due to this velocity is minuscule for large R.
And FYI, these numbers get smaller and smaller for orbits around sun, galaxy and local cluster BECAUSE R gets larger exponentially more than the speeds do. Again this is the right answer, but flat earth enthusiasts seem to deny science at their own parole.
Note: U on the attached graph is the potential energy, which is just the Force rewritten for easier calculations because it is easier to manage scalars vs vectors. But because force is just the () gradient of the potential, these relationships hold perfect. So energy and force are essentially going to have the same relationship here in this graph.
**Note: this is a center of mass two body problem. If you take your body to be the second mass sitting down. You will be rotating in a circular orbit (speed and radius depends on your latitude) around the combined center of mass. The center of mass will be the earth's center of mass because your mass is so small.
==> key point to debunk flat earth proponents:
So to "spin you off", the centrifugal force will have to be GREATER than gravity. If you lived at the equator which is the place you will "spin off" first, the earth's centrifugal acceleration has to be greater than 9.8 meters per second^2. To calculate the speed needed with the earth's known radius, use the equation for centrifugal acceleration v^2/R = 9.8, solve for v and you get a rim velocity of 17,689.69 miles per hour!
And guess what? That is the known escape velocity of the earth (how fast rockets have to go to escape the earth's gravity well)! How cool is that!!
Centrifugal Force and Why things Weigh Less At the Equator vs the Poles
What about the effect of the spinning Earth? Near the equator, the acceleration is 0.0339 meter/sec2. Accelerometers do measure this force. But compared to gravity, it is small. Only 1/300 as large as gravity. Only scientific accelerometers are going to notice this. And they do notice it.
As Earth rotates, any object on its surface will feel a centrifugal force directed outward from the center of Earth and generally in the direction of local zenith. This causes Earth to be slightly bulgedout at the equator compared to the poles, which you can see from the difference between its equatorial radius of 6,378.14 km versus its polar radius of 6,356.75 km: a polar flattening difference of 21.4 kilometers. This centrifugal force also has an effect upon the local surface acceleration by reducing it slightly at the equator compared to the poles. At the equator, one would measure a value for ‘g’ that is about 9.78 m/sec2 while at the poles it is about 9.83 m/sec2
What about the effect of the spinning Earth? Near the equator, the acceleration is 0.0339 meter/sec2. Accelerometers do measure this force. But compared to gravity, it is small. Only 1/300 as large as gravity. Only scientific accelerometers are going to notice this. And they do notice it.
As Earth rotates, any object on its surface will feel a centrifugal force directed outward from the center of Earth and generally in the direction of local zenith. This causes Earth to be slightly bulgedout at the equator compared to the poles, which you can see from the difference between its equatorial radius of 6,378.14 km versus its polar radius of 6,356.75 km: a polar flattening difference of 21.4 kilometers. This centrifugal force also has an effect upon the local surface acceleration by reducing it slightly at the equator compared to the poles. At the equator, one would measure a value for ‘g’ that is about 9.78 m/sec2 while at the poles it is about 9.83 m/sec2
More Flat Earth Misinformation  Maybe put atmosphere Stuff Here (Gravity and Rotation Misunderstandings
Flat earthers like to use images like (two on bottom row) to try to convince people that the atmosphere cannot possibly rotate with the earth because the outer atmosphere would have to be going faster (and gravity doesn't exist..lol). The problem is their scale and numbers they use for speed are totally fabricated!
While that is true the upper atmosphere is traveling faster, gravity and drag forces keep it moving with the rotating earth just fine.
The TANGENTIAL velocity would be a little greater, but when you do the calculations it is only 16 MILES PER HOUR faster in the upper atmosphere than the surface at the equator (where it is maximum). Flat earthers' LITERALLY made these numbers up! And it is easy to calculate these numbers.
Note: Karmon line is the well accepted boundary between the atmosphere and space but it is not a hard boundary, just a convenience for calculations.
Also worth noting is the earth's atmosphere is like a thin bubble around the earth compared to whole size of our planet. This image below (Top Row) shows with the thin yellow line the upper atmosphere to scale with curvature. Flat earthers' images and numbers are just wrong period! They make earth too small, the atmosphere too large and the speeds way too high! They just don't understand the scale of things!
Flat earthers like to use images like (two on bottom row) to try to convince people that the atmosphere cannot possibly rotate with the earth because the outer atmosphere would have to be going faster (and gravity doesn't exist..lol). The problem is their scale and numbers they use for speed are totally fabricated!
While that is true the upper atmosphere is traveling faster, gravity and drag forces keep it moving with the rotating earth just fine.
The TANGENTIAL velocity would be a little greater, but when you do the calculations it is only 16 MILES PER HOUR faster in the upper atmosphere than the surface at the equator (where it is maximum). Flat earthers' LITERALLY made these numbers up! And it is easy to calculate these numbers.
Note: Karmon line is the well accepted boundary between the atmosphere and space but it is not a hard boundary, just a convenience for calculations.
Also worth noting is the earth's atmosphere is like a thin bubble around the earth compared to whole size of our planet. This image below (Top Row) shows with the thin yellow line the upper atmosphere to scale with curvature. Flat earthers' images and numbers are just wrong period! They make earth too small, the atmosphere too large and the speeds way too high! They just don't understand the scale of things!
It's welldocumented fluid dynamics that causes the air to mostly rotate with the Earth. Deviations from matching that rotation are called Wind. Same goes all the way up. And you failed to calculate how much faster it would be spinning and show that this effectsize cannot be accounted for with existing fluid dynamic models.
Once again, air molecules also do not lose their existing rotational momentum.
They are therefore subject freely to fluid dynamics  pressure changes caused by heating and cooling, and all the rest. Having wind going different directions on a rotating Earth is not a violation of any physical law.
**Atmosphere spinning**
This is the danger of conflating angular motions with linear speeds. The atmosphere aloft would be moving at the same angular rate as the atmosphere below it  any deviation from this would be Wind and only that would cause drift.
Since the atmosphere becomes less dense with altitude (thanks to Gravity  on Flat Earth shouldn't all air be the same 'density'?) fluid dynamics has less impact and pressure differentials can become more extreme, creating the Jet Stream, atmospheric heating from solar radiation produces the large scale Polar, Ferrel, and Hadley circulation cells, and the Coriolis force all play roles.
Once again, air molecules also do not lose their existing rotational momentum.
They are therefore subject freely to fluid dynamics  pressure changes caused by heating and cooling, and all the rest. Having wind going different directions on a rotating Earth is not a violation of any physical law.
**Atmosphere spinning**
This is the danger of conflating angular motions with linear speeds. The atmosphere aloft would be moving at the same angular rate as the atmosphere below it  any deviation from this would be Wind and only that would cause drift.
Since the atmosphere becomes less dense with altitude (thanks to Gravity  on Flat Earth shouldn't all air be the same 'density'?) fluid dynamics has less impact and pressure differentials can become more extreme, creating the Jet Stream, atmospheric heating from solar radiation produces the large scale Polar, Ferrel, and Hadley circulation cells, and the Coriolis force all play roles.
Helicopter Paradox
If the earth was spinning, flying vehicles could hover and wait for their destination to come to them.
Actually a fairly interesting one  I've heard it before from sincere questioners. Suppose, for a moment, that the question is a fair one.
What would this mean? It would mean that the wind isn't rotating with the earth. The speed they mention is ``over 1000 mph''. If the air isn't rotating with the earth, then it follows that the wind speed is always over 1000 mph (wind is relative motion between you and the air). It's not, so we deduce that the air rotates with the earth.
So, how much force would that generate on a vehicle flying? The formula for the drag force due to the air.
Flat earthers say that gravity would have to magically and inexplicably drags the atmosphere in perfect synchronization with the earth.
It is not really magically, it's called drag (drag is sort of like `friction' but with fluids instead of solids).
They also claim that rain, fireworks, etc. would behave differently if both the earth and the atmosphere were spinning. This is simply false; they wouldn't. Let's go to Wikipedia/Centrifugal Force. We find the forces for rotating frames.
If the earth was spinning, flying vehicles could hover and wait for their destination to come to them.
Actually a fairly interesting one  I've heard it before from sincere questioners. Suppose, for a moment, that the question is a fair one.
What would this mean? It would mean that the wind isn't rotating with the earth. The speed they mention is ``over 1000 mph''. If the air isn't rotating with the earth, then it follows that the wind speed is always over 1000 mph (wind is relative motion between you and the air). It's not, so we deduce that the air rotates with the earth.
So, how much force would that generate on a vehicle flying? The formula for the drag force due to the air.
Flat earthers say that gravity would have to magically and inexplicably drags the atmosphere in perfect synchronization with the earth.
It is not really magically, it's called drag (drag is sort of like `friction' but with fluids instead of solids).
They also claim that rain, fireworks, etc. would behave differently if both the earth and the atmosphere were spinning. This is simply false; they wouldn't. Let's go to Wikipedia/Centrifugal Force. We find the forces for rotating frames.
The first term is the Euler force, which is about a spinning system that is spinning at a changing rate. For the earth, which is roughly spinning at a constant speed, this contribution is zero.
The second term is the Coriolis force, which depends on the rate of spinning and the velocity of the object. You probably won't be surprised to learn that the earth spins very slowly; only 15 degrees per hour (twice as slow as the hour hand on your clock). This force is VERY SMALL! It would deflect the tennis ball on a Rafael Nadal serve less than a millimeter.
Finally, there's the centrifugal force. It's cancelled by gravity; after all, the frame is rotating because of gravity. Not exactly; in fact, gravity pulls you down which causes friction with the rotating surface which is what attaches you to the rotating frame.
Anyway, this 'layer has friction with layer' type of explanation works sort of nicely. The viscosity is a material property that we can use in a few specific models to properly calculate this sort of stuff.
The earth has been spinning for a few billion years. The entire atmosphere moves with it. There's no magic, just some physics.
However, the air isn't uniform. We already considered this for clouds; there's differences in density, amount of moisture, temperature and so on. Pressure differences also happen  they are related to the local weather.
The earth's friction to the air and the air's viscosity are one part of the story. If we look at smaller scales, we need more details. All of these details are significant on small scales, and cause things like wind, clouds, and so on  what is called weather.
The second term is the Coriolis force, which depends on the rate of spinning and the velocity of the object. You probably won't be surprised to learn that the earth spins very slowly; only 15 degrees per hour (twice as slow as the hour hand on your clock). This force is VERY SMALL! It would deflect the tennis ball on a Rafael Nadal serve less than a millimeter.
Finally, there's the centrifugal force. It's cancelled by gravity; after all, the frame is rotating because of gravity. Not exactly; in fact, gravity pulls you down which causes friction with the rotating surface which is what attaches you to the rotating frame.
Anyway, this 'layer has friction with layer' type of explanation works sort of nicely. The viscosity is a material property that we can use in a few specific models to properly calculate this sort of stuff.
The earth has been spinning for a few billion years. The entire atmosphere moves with it. There's no magic, just some physics.
However, the air isn't uniform. We already considered this for clouds; there's differences in density, amount of moisture, temperature and so on. Pressure differences also happen  they are related to the local weather.
The earth's friction to the air and the air's viscosity are one part of the story. If we look at smaller scales, we need more details. All of these details are significant on small scales, and cause things like wind, clouds, and so on  what is called weather.