# Kinetic Energy of Protons

#### lilymay992

Homework Statement
Hi! So for my a levels I’ve been doing practice papers and I’m stuck. I have to calculate the kinetic energy of a proton after acceleration except I’m only given the charge of +1.6x10^-19 , a potential difference of 80kV, and a mass of 1.7x10^-27kg
Homework Equations
Kinetic energy = 1/2 x mass x velocity^2
So first I tried to use KE=1/2 x m x v^2 but then realised I didn’t have the velocity and I can’t figure out a way to obtain it. I then tried to work out the energy using a different equation, W= q x v but that left me with 1.28x10^-14 J which seemed too small.

I also then have to calculate the maximum speed of the proton which I’m confused at how to do if I don’t have the velocity.

Related Introductory Physics Homework Help News on Phys.org

#### Orodruin

Staff Emeritus
Homework Helper
Gold Member
2018 Award
You have the charge and you have the change in electric potential. What does this mean for the change in the potential energy of the proton and where does this potential energy go during acceleration?

• lilymay992

#### lilymay992

Oh so do I use V= p.e. / q because the electrical energy has been transferred to kinetic energy during the acceleration?

#### Orodruin

Staff Emeritus
Homework Helper
Gold Member
2018 Award
That does seem like a viable option, yes.

• lilymay992

Homework Helper
Gold Member
2018 Award