# Strength of magnetic field required to balance gravitational force

astru025

## Homework Statement

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?

## Homework Equations

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

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## Answers and Replies

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

Gold Member
try $vB=mg$!

Homework Helper
try $vB=mg$!

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.

Homework Helper

## Homework Statement

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?

## Homework Equations

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

## The Attempt at a Solution

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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.

Gold Member
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.

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!

Homework Helper
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!

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!