1. A boy throws a ball vertically upwards from ground level. If the ball reaches a maximum height of 250 m and the gravitational acceleration is 9.8 m/s2, with what speed did the boy throw the ball?   50 m/s   70 m/s   35 m/s   10 m/s   Hint Half-n-half Clue   2. _______ is the capacity to do work.   Energy   Pressure   Force   Half-n-half Clue   3. When a current is supplied by a battery, _______ energy is converted to electrical energy.   nuclear   chemical   mechanical   Half-n-half Clue   4. The maximum amount of work that can be done by a 70 kW machine in 12 seconds is   6 J   840 J   6 kJ   840 kJ   Half-n-half Clue   5. A pebble is dropped from the top of a cliff 60 m in height. The kinetic energy of the pebble equals twice its potential energy at a distance of _______ above sea level.   20 m   45 m   15 m   30 m   Half-n-half Clue   6. By definition, work is done when a _______ moves through a distance.   mass   force   pressure   Half-n-half Clue   7. A body loses 5292 J of potential energy in falling through 90 m. If the gravitational acceleration is 9.8 m s-2, then the body has a mass of   540 kg   6 kg   882 kg   59 kg   Half-n-half Clue