1. The SI unit of power is   Joule   Watt   Volt   Hint Half-n-half Clue   2. 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.   45 m   15 m   30 m   20 m   Half-n-half Clue   3. The energy possessed by a body due to its position or configuration is called _______ energy.   potential   thermal   sound   kinetic   Half-n-half Clue   4. A body loses 490 J of potential energy in falling through 10 m. If the gravitational acceleration is 9.8 m s-2, then the body has a mass of   50 kg   98 kg   49 kg   5 kg   Half-n-half Clue   5. By definition, work is done when a _______ moves through a distance.   force   pressure   mass   Half-n-half Clue   6. A body loses 1764 J of potential energy in falling through 45 m. If the gravitational acceleration is 9.8 m s-2, then the body has a mass of   39 kg   180 kg   4 kg   441 kg   Half-n-half Clue   7. If an engine does 528 J of work in 6 seconds, its average power is   522 W   534 W   3168 W   88 W   Half-n-half Clue