Rate of loss of potential energy

AI Thread Summary
The calculated rate of loss of potential energy is 175 W based on the formula PE = mgh, using a height of 0.51 m. However, the answer key states 80 W, leading to confusion about the discrepancy. Some participants suggest that the answer key might actually mean 180 W when considering significant figures, as 175 W rounds up to 180 W. The possibility of a typo in the answer key is also discussed. The conversation concludes with gratitude for the input from other users.
songoku
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Homework Statement
Please see below
Relevant Equations
PE = mgh
1678204756709.png


I got answer for (a), which is 0.51 m

For (b), loss of potential energy = 35 x 9.81 x 0.51 = 175 J
Rate of loss of potential energy = 175 J / 1 s = 175 W

But the answer key is 80 W. Where is my mistake?

Thanks
 
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I think your answer of 175 W is correct.
 
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songoku said:
Homework Statement:: Please see below
Relevant Equations:: PE = mgh

But the answer key is 80 W
If one were adhering to the rules of significant figures, your 175 W (175.103048... on my calculator) would round up to 180 W.

Is it possible that the answer key says "180 W" instead of "80 W"?
 
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jbriggs444 said:
If one were adhering to the rules of significant figures, your 175 W (175.103048... on my calculator) would round up to 180 W.

Is it possible that the answer key says "180 W" instead of "80 W"?
Maybe it is a typo, the answer is written 80 W.

Thank you very much TSny and jbriggs444
 
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