energy problem

[Brown Arrow]

1. The problem statement, all variables and given/known data
what is the speed of en electro, initially at rest,if a total work of 50keV is done on it?
1eV=1.6*10-19j me=9.11*10-31kg

2. Relevant equations
relastic energy equaltion.


3. The attempt at a solution

i converted the total work to total energy

Etotal=8*10-15

then i set Etotal=(mc2)/(1-(v/c)2)1/2
when i try solving it i keep getting sqrt of a negative #
could someone tell me where im going wrong

[zhermes]

You have to include the rest mass as part of the total energy, not just the work done on the particle

[Brown Arrow]

oh i see thanks!
let me see if it works

[Brown Arrow]

yeah it works thanks again !