Answer:
158.6 J
Step-by-step 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