# Understanding the forces involved in a bounce from a collision?

A rock is thrown towards a window, and hits it. The window does not break and the rock reverses its direction and falls under the window.

My question is, under this circumstance since the rock reversed it's direction of movement I want to say that the force exerted by the window was larger than that of the rock because if they were equal, the rock would simply stick to the window and slide down until it reaches the bottom.

However, the answer to this problem claims that the window and the rock had the same force. Can someone explain me what is going on?

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