1) A toy rocket-launcher contains a spring with a spring constant of 35 N/m. How much must the spring be compressed to store 1.5 J of energy?
2) A box is connected to a spring is extended to 200mm, and it stored 3578J of energy. Find the force.

During cooling, the kinetic energy of the molecules falls. why does this happen? a.the motion of the molecules increases. b. the motion of the molecules slows down. c.the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.