# B How Horsepower is equal to 550 ft lb/s ?

1. Jan 6, 2017

### PHYSICS5502

How did James Watt found out that one horsepower is equal to 550 ft lb/s ? There must be some sort of derivation or something that he did.Can anyone show me that derivation.

Last edited: Jan 6, 2017
2. Jan 6, 2017

### Nidum

From observation of the haulage power of a horse . He fiddled the answer a lot though for commercial purposes .

Boulton and Watt manufactured steam engines .They were a bit notorious for making exaggerated claims about the power and economy of their engines compared to horses .

https://en.wikipedia.org/wiki/Horsepower#History_of_the_unit

Last edited: Jan 6, 2017