Work problem

[strugglin-physics]

How much work is required to stop an electron (m = 9.11×10-31 kg) which is moving with a speed of 1.86×106 m/s?

Ef-Ei=W
Kenetic E - Potential E = Work
I don't think there is any potential energy in this case...

I'm a bit stuck. Any suggestions?

[Doc Al]

Keep going. W = \Delta {KE}, so what's the kinetic energy of that electron?

[strugglin-physics]

is the change in kenetic energy 1/2mv^2?

[Doc Al]

The initial KE of the electron is 1/2mv^2; the final is zero. So, yes, the change in KE is (minus) 1/2mv^2.

[strugglin-physics]

Great thank you that was a whole lot easier than I made it out to be!