Question

A rail gun accelerates a projectile from rest by using the magnetic force on a current-carrying wire. The wire has radius r = 5.15·10-4 m and is made of copper having a density of ρ = 8960 kg/m3. The gun consists of rails of length L = 1.32 m in a constant magnetic field of magnitude B = 2.19 T, oriented perpendicular to the plane defined by the rails.