(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A moving proton has 6.4x10^-16 J of kinetic energy. The proton is accelerated by a potential difference of 5000 V between parallel plates.

http://members.shaw.ca/barry-barclay/Self-Tests/test09/elecst17.gif

The proton emerges from the parallel plates with what speed?

A. 8.8x10^5 m/s B. 9.8 x10^5 m/s C. 1.3x10^6 m/s D. 1.8x10^6 m/s

I know that the answer is C, I just don't know how to get there.

2. Relevant equations

q=1.60x10^-19 C

m=1.67x10^-27 kg

E_{k}=6.4x10^-16 J

5000V electric potential difference (I don't really fully grasp what this means. I have something that says electric potential difference = work done in moving test charge/magnitude of test charge [V=ΔE/q])

I know that Kinetic Energy=q|E|d

V=ΔE/q

W=Vq

Fe=kq/r^{2}

|E|=V/d

Then I know the basic kinematics formulas

3. The attempt at a solution

I found work by using W=Vq. I get (5000V)(1.60x10^{-19}C)= 8.00x10^{-16}J

Then I'm lost as to what to do. But:

Using E_{k}=0.5mv^{2}I get the answer A. Is that actually the correct answer and the answer key from the thing he copied/pasted is wrong?

I saw this thread when googling https://www.physicsforums.com/showthread.php?t=168634 , which made me think that.

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# Homework Help: Final velocity of a proton through parallel plates

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