Here is a question from the review packet that I got for mymidterm. A motor used

Question

Here is a question from the review packet that I got for mymidterm. A motor used 120. watts of power to raise a 15-newton objectin 5.0 seconds. Through what vertcle distance was the objectraised? I have formulas to get the answers, I'm just confused on whichones to use, like I know I would need power formula and workformula. Please help me, I don't want to fail. Here is a question from the review packet that I got for mymidterm. A motor used 120. watts of power to raise a 15-newton objectin 5.0 seconds. Through what vertcle distance was the objectraised? I have formulas to get the answers, I'm just confused on whichones to use, like I know I would need power formula and workformula. Please help me, I don't want to fail.

Explanation / Answer

Power is the energy delivered (or work done) per unit time:
P = W / t
Now we know that this power has been used 5 seconds to lift anobject. So, what do we get?
(W / t)(5 sec.) = "work done"
This work has been done against gravity. Now, if we happenedto let go that object, it would restore that energy. That(potential) energy is (by definition of energy &work):
E = F.d , where I denoted the height by d.
It has the same magnitude as the work done. So
(W/t)(5 sec.) = (120 watts)(5sec.)    =    F.d = (15N).d
Then from the equation

(120 watts)(5 sec.) = (15N)d

we can find d.
P = W / t
Now we know that this power has been used 5 seconds to lift anobject. So, what do we get?
(W / t)(5 sec.) = "work done"
This work has been done against gravity. Now, if we happenedto let go that object, it would restore that energy. That(potential) energy is (by definition of energy &work):
E = F.d , where I denoted the height by d.
It has the same magnitude as the work done. So
(W/t)(5 sec.) = (120 watts)(5sec.)    =    F.d = (15N).d
Then from the equation

(120 watts)(5 sec.) = (15N)d

we can find d.

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