Answer:
2/3
Step-by-step explanation:
The work done on the box is ...
Fd = (60 N)(10 m) = 600 N·m = 600 J
The amount of energy the box has as a result is ...
KE = 1/2mv² = (1/2)(8 kg)(10 m/s)² = 400 kg·m²/s² = 400 J
The ratio of box energy to energy input is ...
η = (400 J)/(600 J) = 2/3 . . . ≈ 66.7%
