What is the power output if a 5 N force acts on an object that moves 2 m in the direction of the force?

• A. 2 W
• B. 4 W
• C. 6 W
• D. 8 W

Answer: (B)

Power is the rate at which work is done. When a force acts in the same direction as motion, the work done is W = F × d. Here that’s 5 N × 2 m = 10 joules of work. Power then is P = W / t, so you need the time interval to get a numeric value. If the motion takes 2.5 seconds, P = 10 J / 2.5 s = 4 W, which is why 4 W is listed as the answer. Remember, with different times you’d get different powers: longer times give smaller power, shorter times give larger power (for example, 5 s would give 2 W, 1.25 s would give 8 W).