A wheel is rotated about a horizontal axle at a constant angular speed.Next it is rotated in the opposite direction with the same angular speed.The acceleration at a point on the top of the wheel in the second case as compared to the acceleration in the first case:
A)is in the same direction.
B)is in the opposite direction.
C)is upward.
D)is tangential to the wheel.

Question

Quizplus · Accepted Answer

The acceleration at a point on the top of the wheel is directed towards the center of the circle and is therefore perpendicular to the surface of the wheel. When the wheel is rotating in one direction (first case), the direction of the acceleration is towards the center of the circle, while in the second case (rotating in the opposite direction), the direction of the acceleration is still towards the center of the circle. Therefore, the direction of the acceleration at the top of the wheel remains the same in both cases.

A Wheel Is Rotated About a Horizontal Axle at a Constant