# Electromagnetic fields and force

1. Apr 24, 2007

### dtesselstrom

1. The problem statement, all variables and given/known data
What is the magnitude of the force on the proton in the figure? View Figure

2. Relevant equations
F=q(E+v*B)

3. The attempt at a solution
Ive tried just putting the numbers into that equation provided and it doesn't work so Im guessing there is some more that Im missing. Ive also tried subtracting the two because B and E are in opposite directions but this also didn't work.

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• ###### knight_Figure_34_02.jpg
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2. Apr 26, 2007

### daniel_i_l

You just need that equation. Make sure that you get the directions af the forces right. Are you sure that the force resulting from B and the force form E are in opposite directions?

3. Apr 26, 2007

### Mentz114

$$\vec{F}=q(\vec{E}+\vec{v}\times\vec{B})$$

Speaking of directions, this equation is a vector equation and the x is a cross product.