1. A boy throws a ball vertically upwards from ground level. If the ball reaches a maximum height of 40 m and the gravitational acceleration is 9.8 m/s2, with what speed did the boy throw the ball?   4 m/s   14 m/s   28 m/s   20 m/s   Hint Half-n-half Clue   2. Power is the rate of doing work.   True   False   3. By definition, work is done when a _______ moves through a distance.   pressure   mass   force   Half-n-half Clue   4. A mass of 5 kg is raised through a vertical distance of 90 m. If the gravitational acceleration is 9.8 m s-2, then the potential energy gained by the mass is   4410 J   450 J   882 J   49 J   Half-n-half Clue   5. A pebble is dropped from the top of a cliff 96 m in height. The kinetic energy of the pebble equals twice its potential energy at a distance of _______ above sea level.   72 m   48 m   32 m   24 m   Half-n-half Clue   6. The energy possessed by a body due to its position or configuration is called _______ energy.   kinetic   sound   potential   thermal   Half-n-half Clue   7. If an engine does 648 J of work in 9 seconds, its average power is   72 W   657 W   639 W   5832 W   Half-n-half Clue