Question

A student uses 150 N to push a block of wood up a ramp at constant velocity of 2.6m/s. What is his power output?

Answer 1

Answer:

P= 390 W

Explanation:

In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time.  Work  is a force F applied over a distance x. Matemathicaly it means

P = dW/dt ≈ d(F * x)/dt = xdF/dt + Fdx/dt. If force is constant dF/dt=0 so P=F dx/dt = P*v, where v is velocity, the rate of distance per unit time.

We have force and velocity. Newton is unit of Kg*m/s2, hence

P= 150 kgm/s2 * 2.6 m/s =390 Kgm2/s3 = 390 W, where W is Watts and is an unit of power