Chapter 8, Problem 50A

To determine

Whether the angular acceleration of a toy is positive, negative or zero if it rotates at a constant rate of $5\text{rev/min}$ .

Answer to Problem 50A

Zero

Explanation of Solution

Introduction:

The constant rate of revolution of a toy means that it covers a fixed angular distance in a time.

If in a time, the toy covers a fixed distance or undergoes fixed revolutions in a minute, then its angular velocity must be constant since the angular velocity is basically the time rate change of angular distance.

Now, if the angular velocity of the toy is constant then its angular acceleration will be zero since angular acceleration is the time rate change of angular velocity.

Conclusion:

Hence, the angular acceleration of a toy is zero if it rotates at a constant rate of $5\text{rev/min}$ .