A DVD accelerates uniformly from rest to its operational speed of (570 mathrm{rpm}) in (3.50 mathrm{~s}). (a)

Question:

A DVD accelerates uniformly from rest to its operational speed of \(570 \mathrm{rpm}\) in \(3.50 \mathrm{~s}\).

(a) What is the angular acceleration of the DVD during this time?

(b) What is the angular acceleration of the DVD after this time?

(c) If the DVD comes uniformly to a stop in \(4.50 \mathrm{~s}\), what is its angular acceleration during this part of the motion?

THINKING IT THROUGH.

(a) Once given the initial and final angular velocities, the constant (uniform) angular acceleration can be calculated (Equation 7.12), since the amount of time during which the DVD accelerates is known.

(b) Keep in mind that the operational angular speed is constant.

(c) Everything is given for Equation 7.12, but a negative result should be expected. Why?
Equation 7.12: image text in transcribed