Eriq and Fatima are studying physics... Eriq: I don’t think I believe this whole

Question

Eriq and Fatima are studying physics...

Eriq: I don’t think I believe this whole work-kinetic energy theorem.

Fatima: Oh, really...

Eriq: For example, I helped my friend move a fridge into his dorm room the other day. We started

outside, picked up the fridge, carried it up three flights of stairs, and then pushed it across the floor into

place. But since the box started and ended at rest, I did no work on it, but I definitely was tired and

sweaty.

What is wrong with Eriq’s thinking? (Maximum 2-3 sentences.)

Explanation / Answer

The work done is the force x displacement. Now in this case, there is displacement and force is what used by Eriq which made him tired. Further more, force is proportional to the weight of the fridge.

Secondly, the energy that is spent is equal to the difference of potential energy between the fridge's original position and final position three flights of stairs above. which brings in the difference in height (mg(h2-h1))

so work is not zero and the work done is equal to the energy spent by Eriq which made him ofcourse tired.

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