# Electric Field and Magnetic Field

## Homework Statement

A 6.45 uC particle moves through a region of space where an electric field of magnitude 1220 N/C points in the positive direction, and a magnetic field of magnitude 1.19 T points in the positive z direction. If the net force acting on the particle is 6.45E-3 N in the positive direction, calculate the magnitude of the particle's velocity. Assume the particle's velocity is in the x-y plane.

F=qE
v=1/B(E-Fnet/q)

## The Attempt at a Solution

This is what I did:
using F=qE: (6.45 e-6 C)(1220N/C)= 0.00787 N

Then using V=...
: (1/1.19T)(1220N/C - 6.45 E-3/6.45 e-6)= 184.8 m/s

BUT it keeps telling me my answer is wrong... do I have to put it in the negative direction?

## Answers and Replies

Where does your second equation come from? If we let the "positive direction" be the x-direction, which direction is the velocity pointing in?

The velocity will point in the negative Y direction according to the right hand rule.

The equation comes from:

netForce= qE-qvB

And when you plug all the values in i keep getting: 184.8 m/s but my computer says it is wrong.