[Physics] When I pull a rope attached to a block, does the rope OR the block pull me back? If so, with what force

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I am having a hard time understanding the tension force, especially when thinking about it at a molecular level.

Suppose I have a rope attached to a block which is sitting on frictionless surface. When I pull the rope, the molecular bonds in the rope get stretched. As a result, they try to restore (go back to "normal" position). Does this restoration pull me back or does it pull the other molecular bonds in the rope all the way to the block, until it pulls the block? or both. If the rope does pull me back, it can't be with the same force I pulled it, right? Otherwise the block would not move at all.
Also, if the rope pulls the block, does the block pull the rope back too?

Is it fair to say: The person pulls the rope to the right, and the rope pulls the person to the left. The rope pulls the block to the right and the block pulls the rope to the left.

Can anyone help me understand that?

Best Answer

It may be easier to think of a stretched spring than a rope. A spring pulls its ends together. If you are attached to one end of the spring, and a block is attached to the other, you will be pulled towards each other. The same force is exerted by each end of the spring.

Suppose you had three identical springs identically stretched. One connects you to a wall, then second connects you to a block, and the third the block to a wall. Two identical springs pull you in opposite directions. The forces cancel. The overall effect is the same as if no forces were acting on you.

You can think of a spring as many short springs connected together. Each connection between short springs is pulled equally left and right.

If you have two identical blocks at the end of a spring on a frictionless surface, the forces on the blocks will accelerate them toward each other with identical accelerations.

If you and a block are attached to the spring, you will be pulled toward each other with equal force. Since the block is smaller than you are, the block will have a larger acceleration.