Q1. A car carrying a 77-kg test dummy crashed into a wall at 27m/s and is brought to rest in 0.1 s. demonstrate that the average force exerted by the seat belt on the dummy is 18,760N.
Q2. An astronaut is rotated in a horizontal centrifuge at a radius of 3.3 m. (a) what is the astronaut's speed if the centripetal acceleration has the magnitude of 6.4g? (b) How many revolutions per minute are necessary to produce this acceleration? (c) What is the period of the motion?