posted by help! .
Suppose that high-speed stroboscopic photographs show that the 200-g head of a golf club travels at 51 m/s just before it strikes a 50-g golf ball initially at rest on a tee.
If the club head slows to at 36 m/s (in the same direction) after the collision,
what is the speed of the golf ball just after impact, and
what fraction of the original kinetic energy of the club head was lost to thermal energy? Assume that the mass of the club is concentrated mostly in the head.