# Electromagnetic rail gun

## Homework Statement

An electromagnetic rail gun can fire a projectile using a magnetic field and an electric current. Consider two parallel conducting rails, separated by 0.575 m, which run north and south. A 49.0-g conducting rod is placed across the tracks and a battery is connected between the tracks, with its positive terminal connected to the east track. A magnetic field of magnitude 0.750 T is directed perpendicular to the plane of the rails and rod. A current of 2.00 A passes through the rod.

If there is no friction between the rails and the rod, how fast is the rod moving after it has traveled 8.00 m down the rails? What direction is the force on the rod?

## Homework Equations

F = qVxB (where V and B are vectors)
F = I LxB
a = ILB / m

## The Attempt at a Solution

a= (2.0 A)(0.575m)(0.750T)
a = 0.8625 m/s

I've drawn the picture and can determine (see) that the force in in the North direction. So I just need help figuring out the acceleration. I think there must be some cross products but don't really understand how to do that.

ideasrule
Homework Helper
Didn't you already calculate the acceleration? The unit should be m/s^2, not m/s.

Sorry, I got confused.

So then to answer the actual question I multiply 0.8625 by 8.0 meters

(0.8625)(8.0) = 6.9 m/s^2

Thanks.