1. A spring is stretched 0.65 m from equilibrium by a force of 299 N. (a) Determine the spring constant. (b) Determine the work done on the spring to stretch it 0.25 m from equilibrium.

Two objects of masses m,= 1.5 kg and m2=3.5 kg undergo a one-dimensional head-on collision as shown in Figure. Their initial velocities along x are via = 15 m/s and Vi = -7.5 m/s. The two objects stick together after the perfectly inelastic collision. (a) Calculate the velocity after the collision. (b) Determine how much kinetic energy is lost in the collision