William, who has a mass of 80.0 kg, is driving at 40.0 m/s in his car when he must suddenly slam on the brakes to avoid hitting a deer crossing the road. He hits a tree and strikes the air bag, bringing his body to a stop in 0.500 s. What average force does the air bag exert on him?

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?

Most short-period comets do not have randomly oriented orbits because

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.