# Help with proton moving through magnetic field.

1. Jan 26, 2012

### jhcollaz

1. The problem statement, all variables and given/known data

I need help with a problem I was just given an equation (F =q VxB )at the end of class and expected to solve a problem but im not sure what to do.
A proton is moving at speed 5x106m/s in the magnetic field of magnitude 6x10-2 T indicated in the diagram. a) find the magnitude and direction of the initial magnetic force on the proton. b)what is the magnitude of the acceleration of the proton?
The diagram and work are in the work below. I was not sure what to do so i looked through the book and found another equation.

2. Relevant equations

3. The attempt at a solution
http://imgur.com/l9NBN
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jan 26, 2012

### Bread18

B is the strength of the magnetic field, which you are given. Not sure why you did the working that you did, it doesn't make any sense lol.

3. Jan 27, 2012

### technician

Your equation enables you to calculate the force = Bqv BUT this equation is used when B and v are at right angles. For your diagram you need the component of B at right angles to v.
So your equation should have BSinθ instead of B.
I hope that you can follow this!

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