Answered

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

Verified Answer :

AL2006

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.       

Dracula419

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

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