Question

A lift is moving down with an acceleration equal to the acceleration due to gravity .a body of mass M kept on the floor of the lift is pulled horizontally. if the coefficient of friction is mu ,then frictional resistance offered by the body is

Answer 1

N = normal, m = mass of object, a = acceleration of lift)
mg - N = ma
N = ma - mg
(given a = g)
therefore
N= 0

friction = u.N (N = 0)
hence friction = u.0
= 0