Is this true?
A bicycle wheel is suspended in the air by it’s skewer and made to rotate at a certain velocity. Both the top (12 o’clock) and the bottom of the wheel (6 o’clock) are spinning at the SAME velocity. Sounds logical so far.
Now, place the same wheel on a bicycle and begin to accelerate until a specified velocity is reached. Is the top of the wheel spinning at the same velocity as the bottom of the wheel (the part that is touching the tire to the ground)? Can anyone help?
The bit flattened against the road is moving at a lower velocity than the top of the tire. Since it’s flattened, it’s closer to the axis of rotation, hence moving a bit slower.
Depends on what you choose as your frame of reference. Relative to the ground, the top of the tire is moving at about twice the speed of the bicycle, while the bottom isn’t moving at all.
Spinning implies angular velocity when I think you mean linear, so it wil be the same for both “top” and “bottom” of the wheel. If you were an observer on the wheel you would see no angular velocity of the wheel but the rest of the universe would be spinning compared to y our frame of reference.