I need help with this questions.

a). An overhead garage door has two springs, one on each side of the door. A force of 15 pounds is required to stretch each spring 1 foot. Because of a pulley system, the springs stretch only one-half the distance the door travels. The door moves a total of 8 feet, and the springs are at their natural length when the door is open. Find the combined lifting force applied to the door by the springs when the door is closed.

2 answers

Hookes Law:

Forceeachspring=kx
=15/1 * x

and x will be 1/2 *8
f=60