# Homework Help: Motion of spring mass with charge in magnetic field

1. Nov 10, 2005

### madking153

hi,

got a difficult question to ask :

we can easily find the motion of charge in magnetic field.But now if the charge is attached to a spring, how can we find the general motion ?

is it like a gyroscope ?

thanks

2. Nov 10, 2005

### Astronuc

Staff Emeritus
A charged particle in a magnetic field with move according to $\vec{v}\,\times\,\vec{B}$. How the spring would inflence this depends on the equilibrium position of the spring with respect to the trajectory of the particle.

Have you tried to write out the equation(s) of motion for the system?

3. Nov 10, 2005

### madking153

ya, i dont know is right or wrong -
dv/dt= qBv/m -kx

but the spring's motion is in x y plane ( if z is magnetic field) - how can i decribe the force cause by spring ?

4. Nov 11, 2005

### maverick280857

How about using vectors?

5. Nov 11, 2005

### armandowww

excuse me... how to start a new thread, please...

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