Magnitude of the net force that acts on the charge

1. Jul 27, 2005

Confused5283

A magnetic field has a magnitude of 1.2 10-3 T, and an electric field has a magnitude of 6.0 103 N/C. Both fields point in the same direction. A positive 1.8 µC charge moves at a speed of 2.6 106 m/s in a direction that is perpendicular to both fields. Determine the magnitude of the net force that acts on the charge.

Okay, i know that Fnet=the square root of Fe^2+Fb^2, and after drawing a diagram, i think that they are 2 perpendicular forces, but I don't know what to plug in to the equation, or where to begin.

2. Jul 27, 2005

Allday

you want to start with the Lorentz force law. It states that the vector forces an electric charge will feel from a magnetic and electric field are

F = q(E + v x B) where E, v, and B are vectors and the x denotes the cross product. Pick any direction for the velocity (say the z direction) and then calculate the vector force. I think the other equaiton you have will just give you a magnitude.

3. Jul 27, 2005

Confused5283

thank u so much... that definitely helped...i solved the problem by doing:F=qE F=qvB then (qE)squared +(qvB)squared than i took the square root of that total :)