A rail gun uses electromagnetic forces to accelerate a projectile to very high velocities. The basic mechanism of acceleration is relatively simple and can be illustrated in the following example. A metal rod of mass 50.0 and electrical resistance 0.100 rests on parallel horizontal rails that have negligible electric resistance. The rails are a distance = 5.00 apart. The rails are also connected to a voltage source providing a voltage of = 5.00 .
The rod is placed in a vertical magnetic field. The rod begins to slide when the field reaches the value = 9.80×10-2. Assume that the rod has a slightly flattened bottom so that it slides instead of rolling. Use 9.80 for the magnitude of the acceleration due to gravity.
Find , the coefficient of static friction between the rod and the rails.