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View Full Version : Deflection of bullet by Earth's magnetic field


jkulier
Aug5-08, 10:15 PM
1. The problem statement, all variables and given/known data

A 0.0034kg bullet moves with a speed of 160 m/s perpendicular to the Earth's magnetic field of 5E-5 T. If the bullet has a net charge of 13.5E-9 C, by what distance is it deflected due to the magnetic field after it has traveled 1000m?


2. Relevant equations

radius = mv/qB
theta = arc length/radius

3. The attempt at a solution

First, I found the radius of the circle via: r = (mv)/qB = 8.1E11

Next, I found theta using the arc length of the circle traveled by the bullet divided by the radius of that circle: theta = arc/radius = 1000/8.1E11

Finally, to find the distance it's deflected, I used the triangle approach: tan(theta) = x/1000

However, my answer is incorrect. Any ideas would be great,
thanks in advance.

LowlyPion
Aug5-08, 10:57 PM
Just wondering why you wouldn't apply the Lorentz magnetic force law to identify the acceleration the bullet would be subjected to and than apply that to figure deflection?