Question

Use this formula to solve this problem:

Power (P) = Work (W) ÷ time (t)

Sara's body supplies a force of 300 N to run up a 15 meter hill in 10 seconds.

How much power is involved in Sara's run up the hill?

A.
2 Watts

B.
20 Watts

C.
30 Watts

D.
450 Watts

Answer 1

power is work / time. work is force * distance so it is
=300 * 15 / 10
=4500 / 10
=450Watts or 0.45KiloWatts

Answer 2

Well, you gave us the formula to calculate power from work and time,
but you didn't give us the formula for work. We have to know that.

Work = (force) x (distance)

The work to raise Sara to the top of the hill is

Work = (300 N) x (15 meters)

= 4,500 newton-meters = 4,500 joules .

Now we're ready to use the formula that you gave us. (Thank you.)

Power = (work) / (time)

= (4,500 joules) / (10 seconds)

450 joules/second = 450 watts.