Question

What happens to the springs of a sofa when we sit on it ?

Answer 1

When we sit on a sofa, the force exerted by the body weight compresses the spring and changes its shape.The surface of the sofa caves inside temporarily. However, when we get up , the external force , here our own body weight stops exerting external prssure of the sofa, the spring bounces back to its original shape and the surface of the sofa is restored back to normalcy.