# Physics

posted by Steeve

You are testing a new car in a wind-tunnel for road and wind resistance. At speed of 90.0 km/h you have found that 74.0 % of the total output power of an automobile engine is used in overcoming the resistance of the road and wind against the movement of the car. If the output of a particular car engine is 57.00 HP, what is this resistance (ie what is the force)? Give your answer in Newtons. (Take one HP as 745 Watts.)

1. drwls

Calculate the power requirement , 57 * 745 Watts.
That equals the resistance force times the velocity, if the velocity is in m/s.
Solve for the force. It will be in Newtons.

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