Easy Question on Magnetic Force of Electron

[alvarez16]

Homework Statement

An electron that has a velocity with x component 1.7 x 106 m/s and y component 3.9 x 106 m/s moves through a uniform magnetic field with x component 0.029 T and y component -0.15 T. (a) Find the magnitude of the magnetic force on the electron. (b) Repeat your calculation for a proton having the same velocity.

The Attempt at a Solution

I tried taking the magnitude of the magnetic field, √ 0.0292 + 0.152 = 0.1527 T

Then the magnitude of the velocity, (√ 1.72 + 3.92 ) x 10^3 = 2.609 x 10^3 m/s

So for a) I got: F = Bqv = 0.1527 * - 1.6 x 10^-19 * 2.609 x 10^3 = - 0.637 x 10^-16 N

and for b) I just made it positive and got .637 x 10^-16 N

But both of those answers are incorrect :(

Please help me :(

 

[kuruman]

First you write the velocity and magnetic field vectors in unit vector notation.
Then you find the magnetic force vector from F = q v x B, i.e. take the cross product between the two vectors correctly. Note that, for an electron, q = -e.