A 1500-kg car accelerates from rest to 25 m/s in 7.0 s. What is the average power delivered by the engine? (1 hp = 746 W)
A) 90 hp
B) 80 hp
C) 60 hp
D) 70 hp

Question

Quizplus · Accepted Answer

The work done on the car is equal to the change in kinetic energy, which is (1/2)mv^2 = (1/2)(1500 kg)(25 m/s)^2 = 468,750 J. The average power is work done divided by time, so 468,750 J / 7 s = 66,964.29 W. Converting to horsepower: 66,964.29 W / 746 W/hp ≈ 89.8 hp, which rounds to 90 hp.

A 1500-Kg Car Accelerates from Rest to 25 M/s in 7.0