# Homework Help: Escape velocity of an electron

1. Feb 16, 2010

### kmikias

$$\sqrt{}$$1. The problem statement, all variables and given/known data

What is the escape speed (in m/s) of an electron launched from the surface of a 7.42 cm diameter glass sphere that has been charged to 7.04 nC?

2. Relevant equations

u=kqq/r
KE=1/2MV^2
UO=KE

3. The attempt at a solution
here is what i did
kqq/r = 1/2mv^2
solve for v
v=$$\sqrt{}2kqq/rm$$
i used q = 7.42 square
and mass of electron = 9.11*10^-31
and r = 0.0704/2
....but still my answer is wrong

2. Feb 16, 2010

### collinsmark

I believe you have the value of the sphere's charge, and the diameter of the sphere interchanged.