Question

A figure skater begins spinning counterclockwise at an angular speed of 4.3 π rad/s. During a 4.7 s interval, she slowly pulls her arms
inward and finally spins at 8.9 π rad/s.
What is her average angular acceleration
during this time interval?
Answer in units of rad/s2.
Don't round answer

Answer 1

Her average angular acceleration:

$$\alpha=\frac{\omega_2-\omega_1}{t}$$

$$\alpha=\frac{8.9 π-4.3 π}{4.7}=3.1\frac{rad}{s^2}$$