When a 3600 lb automobile runs out of gas, it is pushed by its unhappy driver and a friend a quarter of a mile (0.250 mi). To keep the car rolling, they must exert a constant force of 175 lb. (a.) How much work do they do? (b.) If it takes them 15 minutes, how much power do they develop? (c.)Expressed in horsepower, how much power do they develop?

2 answers

work=force*distance
if you are allowed to use ft-lbs, you can do it directly with the given units.

b. work/time=power.
change 15 min to seconds, and note

1 HP, = 550 ft.lb./sec.
259.11