1. [-/7 Points] DETAILS OSCOLPHYS2016ACC 7.1.P.001. MY NOTES PRACTICE ANOTHER How much work does a supermarket checkout attendant do on a can of soup he pushes 0.530 m horizontally with a force of 5.40 N? Express your answer in joules and kilocalories. (For each answer, enter a number.) work in joules work in kilocalories kcal2. [-/4 Points] DETAILS OSCOLPHYS2016ACC 7.1.P.006. MY NOTES PRACTICE ANOTHER How much work (in ]) is done by the boy pulling his sister 33 m in a wagon as shown in the figure below? F 30 d O O A Assume no friction acts on the wagon. (Assumed = 33 m and F = 39 N. Enter a number.) W =3. [-/7 Points] DETAILS OSCOLPHYS2016ACC 7.1.P.004. MY NOTES PRACTICE ANOTHER Suppose a car travels 108 km at a speed of 20.0 m/s, and uses 2.20 gallons of gasoline. Only 30% of the gasoline goes into useful work by the force that keeps the car moving at constant speed despite friction. (The energy content of gasoline is 1.30 x 10 ] per gallon.) (a) What is the force (in N) exerted to keep the car moving at constant speed? (Enter a number.) N (b) If the required force is directly proportional to speed, how many gallons will be used to drive 108 km at a speed of 28.0 m/s? (Enter a number.) gallons4. [-/4 Points] DETAILS OSCOLPHYS2016ACC 7.2.P.015. MY NOTES PRACTICE ANOTHER Using energy considerations, calculate the average force (in N) a 61.0 kg sprinter exerts backward on the track to accelerate from 2.00 to 6.00 m/s in a distance of 25.0 m, if he encounters a headwind that exerts an average force of 30.0 N against him. (Enter a number.) N5. [-/4 Points] DETAILS OSCOLPHYS2016ACC 7.2.P.013. MY NOTES PRACTICE ANOTHER A car's bumper is designed to withstand a 4.32 km/h (1.2 m/s) collision with an immovable object without damage to the body of the car. The bumper cushions the shock by absorbing the force over a distance. Calculate the magnitude of the average force (in N) on a bumper that collapses 0.270 m while bringing a 870 kg car to rest from an initial speed of 1.2 m/s. (Enter a number.)6. [-/7 Points] DETAILS OSCOLPHYS2016ACC 7.3.P.017. MY NOTES PRACTICE ANOTHER (a) How much gravitational potential energy (in ]) (relative to the ground on which it is built) is stored in an Egyptian pyramid, given its mass is about 5 x 109 kg and its center of mass is 28.0 m above the surrounding ground? (Enter a number.) (b) What is the ratio of this energy to the daily food intake of a person (1.2 x 10' ])? (Enter your answer as a ratio to the number 1. Enter a number.) :17. [-/7 Points] DETAILS OSCOLPHYS2016ACC 7.3.P.016. MY NOTES PRACTICE ANOTHER A hydroelectric power facility converts the gravitational potential energy of water behind a dam to electric energy. (For each answer, enter a number.) (a) What is the gravitational potential energy (in ]) relative to the generators of a lake of volume 21.0 km (mass = 2.10 x 1015 kg), given that the lake has an average height of 37.0 m above the generators? (b ) Compare this with the energy stored in a 9-megaton fusion bomb. Elake/Ebomb =