Question

A wagon is pulled at a speed of 0.40 meters/sec by a horse exerting an 1,800-newton horizontal force. What is the power of this horse?

Answer 1

The answer is: `720W`

The definition of Power is:

`P=L/t=(vecF*vecs)/t=vecF*vecs/t=vecF*vecv`

The `*` in the last formula indicate a scalar product, defined by:

`vecv.vecw=|v||w|cos(hat(vw))`, the angle `hat(vw)` is `0` because `vecF and vecv` are parallel, so the cosinus is `1`.

So:

`P=1800N*0,40m/s=720W`.