The temperature of a plastic cube is monitored while the cube is pushed 8.7 m across a floor at constant speed by a horizontal force of 28 N. The monitoring reveals that the thermal energy of the cube increases by 85 J. What is the increase in the thermal energy of the floor along which the cube slides?

158.6 J

Explanation:

given,

distance = 8.7 m

force = 28 N

energy increased by 85 J

work done by the force = force * distance

work done by the force = 28 * 8.7

work done by the force = 243.6 J

work done on cube = 85 J

work done on floor = x J

total work done = 85 + x

243.6 J = 85J + x

x = 158.6 J

increase in the thermal energy of the floor along which the cube slides = 158.6 J