Question

A disc rotates through 10 rad in 4 seconds. If the disc start from rest, determine its angular velocity after 4s

Answer 1

With the info given, find the angular acceleration:

$$\alpha=\frac{2\phi}{t^2}.$$

The angular velocity after the 4 s is

$$\omega=\alpha t=\frac{2\phi}{t}=5\text{ rad/s}.$$