# Strength of magnetic field required to balance gravitational force

1. Dec 15, 2013

### astru025

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

A particle with charge q = 4.00 10-6 C and mass m = 1.30 10-4 kg is moving parallel to the Earth's surface at a speed of 1000 m/s. What minimum strength of magnetic field would be required to balance the gravitational force on the particle?

2. Relevant equations

Not sure where to begin... Any help would be really nice!! Thanks.

3. The attempt at a solution
...

2. Dec 15, 2013

### xophergrunge

Begin by looking at the equations for force due to a magnetic field and force due to gravity.

3. Dec 15, 2013

### ShayanJ

try $vB=mg$!

4. Dec 15, 2013

### Curious3141

This is not even dimensionally consistent. Perhaps you ment $Bqv = mg$. But as a general rule, I've found that just throwing equations at the OP before it's clear he/she understands the underlying concepts is a bad idea.

5. Dec 15, 2013

### Curious3141

Forum policy is that you have to show some effort. Start with xophergrunge's suggestion. Then write down any equations you think might be helpful.

6. Dec 15, 2013

### ShayanJ

Yeah sorry,I forgot the q.
But if s\he's given a problem like that,it means s\he was given the equation and its meaning before!

7. Dec 15, 2013

### Curious3141

And if that's the case, s\he can at least make a start on solving the problem and show us what s\he has done!