1. A body loses 1372 J of potential energy in falling through 20 m. If the gravitational acceleration is 9.8 m s-2, then the body has a mass of   196 kg   69 kg   7 kg   140 kg   Hint Half-n-half Clue   2. A machine that produces 144 J of work by using 160 J of energy has an efficiency of   18 J   90 %   16 J   10 %   Half-n-half Clue   3. The energy possessed by a body due to its position or configuration is called _______ energy.   potential   sound   thermal   kinetic   Half-n-half Clue   4. Kinetic energy of a body in motion equals the product of half its mass and the square of its _______   distance   velocity   acceleration   Half-n-half Clue   5. A carton is pulled along the ground for a distance of 6 m. If the average frictional force is 66 N, then the work done is   396 J   6 J   2376 J   66 J   Half-n-half Clue   6. Efficiency of a machine equals   Work Input / (Work Input + Work Output) × 100 %   Work Input / Work Output × 100 %   Work Output / Work Input × 100 %   Work Output / (Work Input + Work Output) × 100 %   Half-n-half Clue   7. The energy acquired by a body because of its motion is called potential energy.   True   False