Student swings a small rubber stopper attached to a string over her head in a horizontal, circular path. The string is 1.50 meters in length and the rubber stopper makes 120 complete circles every minute.

v = 18.84 m/s

Explanation:

Given that,

The length of the string, r = 1.5 m (it will act as radius)

The rubber stopper makes 120 complete circles every minute.

Since, 1 minute = 60 seconds

It means, its frequency is 2 circles every second.

Let we need to find the average speed of the rubber stopper. It can be calculated as follows :

d is distance, and 1/T = f (frequency)

So, the average speed of the rubber stopper is 18.84 m/s.  

80cm/s.

24cm/s.

53.3cm/s.