1) A car's bumper is designed to withstand a 6.48 km/h (1.8 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 0.255 m while bringing a 870 kg car to rest from an initial speed of 1.8 m/s. (Enter a number.) N

2) (a)

How much gravitational potential energy (in J) (relative to the ground on which it is built) is stored in an Egyptian pyramid, given its mass is about 9 10⁹ kg and its center of mass is 51.0 m above the surrounding ground?

(Enter a number.) J

(b)

What is the ratio of this energy to the daily food intake of a person (1.2 10⁷ J)? (Enter your answer as a ratio to the number 1. Enter a number.) :1