Answer to Question #127520 in Classical Mechanics for Ashley

Question #127520

When a 2 kg body is suspended by a spring, the spring is stretched. If the body is pulled down slightly and released, it oscillates up and down. What force is applied on the body by the spring when it passes through the mean position?
1 : Force equal to the gravity
2 : Force equal to the pull
3 : Conservative force
4 : Force equal to the weight of the body

Expert's answer

Answer d. Force equal to the weight of the body

This is because there is no acceleration in the body at the mean position, therefore, the resultant force on it will be zero