Question

A figure skater begins spinning counterclockwise at an angular speed of 4.5 π rad/s. During a 4.8 s interval, she slowly pulls her arms
inward and finally spins at 7.2 π rad/s.
What is her average angular acceleration
during this time interval?
Answer in units of rad/s
2
.

Answer 1

Answer:

$\alpha =1.76\ rad/s^2$

Step-by-step explanation:

Given that,

Initial angular speed of the skater, $\omega_i=4.5\pi\ rad/s$

Final angular speed of the skater, $\omega_f=7.2\pi\ rad/s$

Time interval, t = 4.8 s

We need to find her average angular acceleration  during this time interval. Let $\alpha$ be the average acceleration of the skater. So,

$\alpha =\dfrac{\omega_f-\omega_i}{t}\\\\\alpha =\dfrac{7.2\pi -4.5\pi}{4.8}\\\\\alpha =1.76\ rad/s^2$

So, her angular acceleration is $1.76\ rad/s^2$.