- #1

VanKwisH

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## Homework Statement

A 1200 kg car slows down from 90km/h to 70 km/h in about 5.0s on the level when it is in neutral. Approximately what power ( in watt's and hp ) is needed to keep the car travelling at a constant 80km/h?

## Homework Equations

P = W / t

## The Attempt at a Solution

I really have no idea ............ and

how much does 1hp = in watts and in joules ?

550 ft lbs/s = in joules and watts?