A 100 gram golf ball is moving with a velocity of 20 m/s. It makes a head on perfectly elastic collision with an 8 kilogram steel ball, initially moving with a velocity of 1.2 m/s. Compute velocities of the balls after collision.

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).