Work and Power

Power is the rate at which something does work over a period of time

​Since W = Fd and P = W/t,

We can say that P = Fd/t

An engine reaches its top speed in 7.5 s.
It performs 250,000 J of work in that time.
What is the engine’s power?

Given

(w/ Units):

Formula:

Substitution
(w/ Units):

Answer

(w/ Units):

An engine reaches its top speed in 7.5 s.
It performs 250,000 J of work in that time.
What is the engine’s power?

Given

(w/ Units):

Formula:

Substitution
(w/ Units):

Answer

(w/ Units):

work = 250,000 J

time = 7.5 s

P = w ÷ t

P = 250,000 J ÷ 7.5 s

33,333 W

Can you change how much power you exert?

Yes! If you do work faster, then you will exert more power.

Open up those workbooks!

Complete section 6.1 review on pages 64-65.