1. A ball is dropped from a height of 1.50
m and rebounds to a height of 1.20 m. Approximately how many rebounds will the
ball make before losing 90% of its energy?
2. A gun fires a bullet vertically into a
1.40-kg block of wood at rest on a thin horizontal sheet, Fig. 9-50. If the
bullet has a mass of 24.0 g and a speed of 310 m/s, how high will the block
rise into the air after the bullet becomes embedded in it?