Question

When an old LP turntable was revolving at 33 rpm, it was shut off and uniformly slowed down and stopped in 5.5 s. What was the magnitude of its angular acceleration in rad/s as it slowed?

A. 3.5 rad/s^2
B. 1.0 rad/s^2
C. 0.5 rad/s^2
D. 0.05 rad/s^2

Answer 1

The magnitude of the angular acceleration of the LP turntable as it slowed down and stopped in 5.5 seconds was 3 pi rad/s^2.

Step-by-step explanation:

To find the angular acceleration of the old LP turntable, we can use the formula:

α = (ωf - ωi) / t

where α is the angular acceleration, ωf is the final angular velocity, ωi is the initial angular velocity, and t is the time taken.

In this case, the initial angular velocity is 33 rpm, which is equivalent to 2π * 33 radians per minute. The final angular velocity is 0 (since it stopped). The time taken is 5.5 seconds.

Plugging in the values, we have:

α = (0 - 2π * 33) / 5.5

Simplifying this gives an angular acceleration of -3 π rad/s^2.

Therefore, the magnitude of the angular acceleration is 3 π rad/s^2, which is approximately 9.42 rad/s^2.

The correct option is A. 3.5 rad/s^2.