# Rate of loss of potential energy

• songoku
In summary, for the given problem, the loss of potential energy for object (b) is calculated to be 175 J, with a rate of 175 W. However, the answer key states the rate to be 80 W, which may be a typo.

#### songoku

Homework Statement
Relevant Equations
PE = mgh

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

songoku, jbriggs444 and nasu
songoku said:
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"?

songoku and TSny
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

jbriggs444 and TSny