Speed of electron when kinetic energy given

[gr3g1]

Hey guys, my teacher saked us to solve for the speed of an electron when the kinetic energy is 6.7*10^-19 Joules

So, I fit in the mass of an electron, and the kinetic energy, and solve for v in the 1/2mv^2 equation??

Thanks a lot

 

[fahd]

Hey guys, my teacher saked us to solve for the speed of an electron when the kinetic energy is 6.7*10^-19 Joules
So, I fit in the mass of an electron, and the kinetic energy, and solve for v in the 1/2mv^2 equation??
Thanks a lot

well obviously yes...thats one way of doing it!

 

[jtbell]

For that energy, the classical kinetic energy equation will work fine. If the energy were 100 times larger, you'd probably need to use the relativistic kinetic energy equation, unless your answer didn't have to be very accurate. If the energy were 1000 times larger, you'd definitely need the relativistic equation.