When an automobile moves with constant speed down a highway, most of the
power developed by the engine is used to compensate for the energy transformations
due to friction forces exerted on the car by the air and road. If the power developed by
an engine is 176hp, estimate the total friction force acting on the car when it is
moving at a speed of 29m/s.
convert hp to watts
divide watts by speed
answer is in Newtons
To estimate the total friction force acting on the car, we can use the power developed by the engine and the car's speed. The power developed can be converted into the force applied by the engine using the equation:
Power = Force × Velocity
Rearranging the equation, we have:
Force = Power / Velocity
First, we need to convert the power from horsepower (hp) to watts (W), as the SI unit for power is watts. One horsepower is equal to approximately 745.7 watts. So:
176 hp = 176 × 745.7 W = 130,983.2 W
Now, we can calculate the friction force:
Force = 130,983.2 W / 29 m/s ≈ 4527 N
Therefore, the estimated total friction force acting on the car when it is moving at a speed of 29 m/s is approximately 4527 Newtons.