Alex is asked to move two boxes of books in contact with each other and resting on a frictionless floor. He decides to move them at the same time by pushing on box A with a horizontal pushing force Fp=9.5 N. Here box A has a mass mA=13.1 kg mA=13.1 kg and box B has a mass mB=7.0 kg. The contact force between the two boxes is Fc and N denotes the normal force. Required:
a. What is the acceleration of the two boxes?
b. What is the force exerted on mB by mA?
c. If Alex were to push from the other side on the 7.0 kg box, how would your answer to part (b) change?

Aball is thrown upward. at a height of 10 meters above the ground, the ball has a potential energy of 50 joules (with the potential energy equal to zero at ground level) and is moving upward with a kinetic energy of 50 joules. what is the maximum height h reached by the ball? consider air friction to be negligible. 1. h ≈ 10 m 2. h ≈ 50 m 3. h ≈ 30 m 4. h ≈ 40 m 5. h ≈ 20 m 003 10.0 points which of the two object shown below has the greatest kinetic energy? a m b 1 2 m v 2v 1. kinetic energies are the same. 2. a 3. b 4. unable to determine. 004 10.0 points tim, with mass 74.6 kg, climbs a gymnasium rope a distance of 3.1 m. the acceleration of gravity is 9.8 m/s 2 . how much potential energy does tim gain? answer in units of j. 005 10.0 points a car is moving at 64 miles per hour. the kinetic energy of that car is 5 × 105 j. how much energy does the same car have when it moves at 111 miles per hour? answer in units of j. 006 10.0 points an 102 kg man climbs up a 1 m high flight of stairs. the acceleration of gravity is 9.81 m/s 2 . w