# Homework Help: Position Varying Electric Potential

1. Feb 12, 2010

### Refrost

http://img168.imageshack.us/img168/3786/66134795.png [Broken]

Part one was simple enough, just insert the variables in the equation given

V = (5)(92)(7) - (9)(9)(6) - (9)(72) = 1908 V

Part two, three and four is where I am getting confused.

Usually I would use triangles to figure out components but I am unable to figure out the direction of the field just based on the information given.

I'm not sure if I am thinking about this the wrong way or if I am misunderstanding some of the information given. Any thoughts that could get me thinking in the right direction would be greatly appreciated. Thanks in advance.

Last edited by a moderator: May 4, 2017
2. Feb 12, 2010

### kuruman

Use

$$\vec{E}=- \vec{\nabla} V$$

3. Feb 12, 2010

### Refrost

Thanks for the quick response. I got it.

Just take the derivative with respect to the component you you're looking for and change the +/- sign.

Thanks!