Question

A disc rotating at angular speed of 10 rad S ^ - 1 is slowed down by a uniform angular acceleration to a speed of 4 rad s ^ -1 in 3 s. What is the angular acceleration?

Answer 1

To find the angular acceleration, we can use the formula:

Angular acceleration (α) = (Final angular velocity (ωf) - Initial angular velocity (ωi)) / Time (t)

Given: Initial angular velocity (ωi) = 10 rad/s Final angular velocity (ωf) = 4 rad/s Time (t) = 3 s

Using the formula, we can calculate the angular acceleration as follows:

α = (ωf - ωi) / t = (4 rad/s - 10 rad/s) / 3 s = (-6 rad/s) / 3 s = -2 rad/s^2

Therefore, the angular acceleration of the disc is -2 rad/s^2. The negative sign indicates that the disc is slowing down, which is consistent with the given information that it is being "slowed down by a uniform angular acceleration."