Question

A dim but resourceful student has a summer job in a factory moving boxes. The 50 kg student finds that if he runs at a speed of 5.8 m/s and then dives head-first into the boxes, he can move them across the floor. If the boxes have a mass of 65 kg and the force of friction between the boxes and the floor is 382 N, how far will he move the boxes after hitting them six times

Answer 1

10.2 m

Step-by-step explanation:

During the collision, momentum is conserved. Assuming the student is not moving after he hits the boxes:

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

(50 kg) (5.8 m/s) + 0 = 0 + (65 kg) v

v = 4.46 m/s

After the collision, energy is conserved. The kinetic energy of the boxes is converted to work done by friction.

KE = W

½ mv² = Fd

½ (65 kg) (4.46 m/s)² = (382 N) d

d = 1.69 m

The boxes move 1.69 meters each time the student hits it. After 6 times, the boxes will move a total distance of 10.2 meters.