"A rod with length L , mass m and resistance R slides without friction down parallel conducting rail of

Question

negligible resistance . the rails are connected together at bottom, forming a conducting loop with the rod
the plain of the loop makes angle Z wih horizontal , a uniform vertical magnetic field B exist
througth the region perpendicular to the plane . show that the rod acquire a velocity whose magnetude

v = (mgR sinZ)/square of(BLcosZ)
and
show that the rate at which the internal energy of the rod is increasing is equal to the rate at which
the rod is losing gravitational potential energy

Answer 1

the ans is totally wrong. v should depend on time t. there is no t in v = (mgR sinZ)/square of(BLcosZ) .