Answer
a) We know that when the laser moves away from the center then the increasing radius will cause the angular speed of the disk to decrease so that the linear speed remains constant.
b) $v=50.0\frac{rad}{s}$
c) $\omega=20.8\frac{rad}{s}$
d) $a_{avg}=-7.31\times 10^{-3}\frac{rad}{s^2}$
Work Step by Step
(a) We know that when the laser moves away from the center then the increasing radius will cause the angular speed of the disk to decrease so that the linear speed remains constant.
(b) As $\omega=\frac{v}{r}$
We plug in the known values to obtain:
$v=\frac{1.25}{0.0250}$
$v=50.0\frac{rad}{s}$
(c) We can find the angular speed as follows:
$\omega=\frac{v}{r}$
We plug in the known values to obtain:
$\omega=\frac{1.25}{0.0600}=20.8\frac{rad}{s}$
(d) We know that
$a_{avg}=\frac{\omega_f-\omega_i}{\Delta t}$
We plug in the known values to obtain:
$a_{avg}=\frac{20.8-50.0}{66.5min\times 60\frac{s}{min}}=-7.31\times 10^{-3}\frac{rad}{s^2}$
