Need some with this physics question?
a new car model is described as having 340 horsepower. at this horsepower, the car’s engine produces 900 kilowatts of heat as it operates. what is the engine’s efficiency?
a) 22%
b) 28%
c) 37%
d) 46%

The only piece of information you need that the question doesn't tell you is:

1 horsepower = 746 watts

So 340 horsepower = 253,640 watts

-- The output of the engine is 253.640 kW useful energy and 900 kW waste heat.

-- The engine is using 1,153.640 kW total energy.

-- The useful output is 253.640 kW.

-- Efficiency is (253.640 kW) / (1,153.640 kW)

Efficiency = 21.99 %

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.