# Homework Help: Electrostatic potential and velocity

1. May 21, 2010

### ryukyu

1. The problem statement, all variables and given/known data

Point A is at an electrostatic potential of +1V relative to point B in a vacuum. An electron initially at rest at B moves to A. What is its velocity in m/s?

2. Relevant equations

E = PE + KE
PE= J/q * q
KE = 0.5 mv^2 (where v = velocity)

3. The attempt at a solution
Based on the definiton of an electron volt (eV), the energy of the electron is 1eV or 1.6E-19 Joules.

In solving the first equation:
1.6E-19 J = 1 J/C * e- + 0.5mv^2
e-= 1.6E-19C
based on my error (whatever that may be)
0 = 0.5mv^2 which means v=0, this doesn't seem correct.

Any suggestions?

2. May 21, 2010

### Char. Limit

Re: Velocity

Shouldn't the charge of the electron be negative? Then you'd end up with

$$2x=.5mv^2$$

Where x is the 1.6*10^-19...

3. May 21, 2010

### ryukyu

Re: Velocity

Thanks,

I knew it was something simple that I had missed.

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