1. The maximum amount of work that can be done by a 90 kW machine in 12 seconds is   8 J   1080 J   8 kJ   1080 kJ   Hint Half-n-half Clue   2. A mass of 100 kg is moved vertically upwards through a distance of 8 m. If the gravitational acceleration is 9.8 m s-2, then the work done against gravity is   7840 J   980 J   78.4 J   800 J   Half-n-half Clue   3. A carton is pulled along the ground for a distance of 6 m. If the average frictional force is 87 N, then the work done is   87 J   522 J   6 J   3132 J   Half-n-half Clue   4. The SI unit of power is   Joule   Watt   Volt   Half-n-half Clue   5. Efficiency of a machine equals   Work Input / (Work Input + Work Output) × 100 %   Work Input / Work Output × 100 %   Work Output / (Work Input + Work Output) × 100 %   Work Output / Work Input × 100 %   Half-n-half Clue   6. A body loses 1176 J of potential energy in falling through 40 m. If the gravitational acceleration is 9.8 m s-2, then the body has a mass of   3 kg   29 kg   392 kg   120 kg   Half-n-half Clue   7. Both work and heat are measured in Joules.   True   False