Final answer:
The angular velocity of the pulley is 63 degrees/s.
Step-by-step explanation:
The angular velocity of the pulley can be calculated using the formula:
angular velocity = linear velocity / radius
Given that the linear velocity of the chain is 4.2 cm/s and the radius of the pulley is 12 cm, we can substitute the values into the formula:
angular velocity = 4.2 cm/s / 12 cm = 0.35 rad/s
To convert the angular velocity from radians per second to degrees per second, we use the conversion factor:
1 rad/s = 180 degrees/s
Therefore, the angular velocity of the pulley is:
0.35 rad/s * 180 degrees/s = 63 degrees/s