How Much Work Is Needed to Move a Charge Between Two Points?

[Avis]

Homework Statement

Points A and B are 4.8cm and 7.2cm away from a point charge of -6.2$$\mu$$C at point C. AC and CB are at right angles.

a. How much work must be done in moving a 2.0x10^-12C charge from A to B
b. what is the potential difference between points A and B?

Ive been working at this problem with a friend for about a half hour. I have No idea what to do. Everything we tried failed.

 

[davieddy]

I would answer b) first.

 

[Avis]

i tried that.. but maby iwas using the wrong equation. Which equation should i be using?

 

[davieddy]

The one which tells you the potential at distance r from a charge Q

 

[Avis]

so V=kq/r. I tried this. It did not work.