Metal rod of mass 1kg moves on two horizontal rails with the

Metal rod of mass 1kg moves on two horizontal rails with the constant velocity. The coefficient of kinetic friction between the rod and rails is 0.01. The distance between rails is 1m. The rod carries a current of 1A. What vertical magnetic field is needed to keep the rod moving? mT.

Solution

Here ,

mass of rod , m = 1 Kg

coefficient of friction , uk = 0.01

distance , d = 1 m

current , I = 1 A

let the magnetic field is B

for the rod to move with constant speed

B * I * L = uk *m * g

B * 1 * 1 = 0.01 * 1 * 9.8

B = 0.098 T = 98 mT

the magnetic field needed is 98 mT