A ball is moved from point A to point B, to point C, to point D, to point E, and back to point A. So, to make things easier... here's a diagram of the problem.(adsbygoogle = window.adsbygoogle || []).push({});

http://img181.imageshack.us/img181/125/conservativeforcesvy3.jpg [Broken]

We were asked to prove (mathematically) the concept that gravity (in this diagram) is a conservative force, and why the angle in the diagram is disregarded.

The following equations were given (and I don't really understand them )...

W = W (A to B) + W (B to C) + W (C to D) + W (D to E) + W (E to A)

W = 0 + (-mgh) + 0 + (-mgh) + (mgh)

W = 0 <--- This has to be proven as well.

I'm also wondering whyW (D to E)became(-mgh)instead of Fxcos(theta).

Help please... Thanks in advance!

--- Jamie

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# Homework Help: Work by Gravity / Conservative Forces

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