# In the case of a ball swinging in circular motion on a rope, w/out gravity or air resistance, what is the force pulling outward on the rope? [duplicate]

This question already has an answer here:

I'm thinking it is either the tension due to the ball, or the ball's centrifugal force. But the thing is, are these two forces the same in the conditions I've set (no gravity, no air resistance)?

After all, the centripetal force would be due to the tension on the ball from the rope. Since the centrifugal force is essentially the opposite of the centripetal force, then it would be equal to the tension on the rope from the ball, right?

## marked as duplicate by Aaron Stevens, GiorgioP, Chris♦, Yashas, Jon CusterMay 2 at 14:48

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• F=ma and as the ball is constantly changing velocity due to direction change it must have an a. So the F that is pulling is due to the ball's acceleration. – PhysicsDave May 1 at 0:57
• You are making a distinction between "tension due to the ball on the rope" and "tension due to the rope on the ball" when in reality these are the same thing. There is just tension. Especially if you are looking at the ball. It has a tension force acting on it. That is it – Aaron Stevens May 1 at 1:13

## 1 Answer

I'm thinking it is either the tension due to the ball, or the ball's centrifugal force.

The outward pointing real force acting on the rope is the tension due to the ball. The ball’s centrifugal force is a fictitious force which acts on the ball and not on the rope, and it only exists in the rotating reference frame.

There is also a centrifugal force acting on the rope in the rotating reference frame, but like all fictitious forces it is proportional to the mass of the object. So assuming the rope is light the force would be small