Question

Lift is going up with acceleration g. A mass M placed on the floor of the lift is dragged parallel to the surface. If coefficient of friction is $\mu$, friction force due to the body is

• A. $\frac{\mu }{Mg}$
• B. 0
• C. Mg
• D. $\mu$ Mg

Answer 1

Answer: (B)

0

When lift falls freely the normal reaction on block

$N-mg=mg$

$N=0$

so friction force acts on the block=$\mu N=0$