Rate of loss of potential energy

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SUMMARY

The discussion centers on the calculation of the rate of loss of potential energy, where the user calculated a value of 175 W based on the formula PE = mgh, using a mass of 35 kg and a height of 0.51 m. The discrepancy arises with the answer key, which states 80 W, leading to speculation about a possible typo. The correct calculation confirms that 175 W is accurate, and when considering significant figures, it could round to 180 W, suggesting a potential miscommunication in the answer key.

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  • Understanding of gravitational potential energy (PE = mgh)
  • Basic knowledge of significant figures in calculations
  • Familiarity with units of power (Watts)
  • Ability to perform unit conversions and rounding
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songoku
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Homework Statement
Please see below
Relevant Equations
PE = mgh
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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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