Answer:
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.
I think you forgot to give the options along with the question. I am answering the question based on my knowledge and research. It is <span>possible to tell if objects in space are moving closer to us or farther away based on several procedures like parallax and standard candles. I hope the answer has come to your help.</span>
So you can use the equation force = mass x acceleration to do 2 x 5 to get 10 N