A block `A` of mass `2 kg` rests on another block `B` of mass `8 kg` which rests on a horizontal floor. The coefficient of friction between `A` and `B` is `0.2` while that between `B` and floor is `0.5`.When a horizontal floor `F` of `25 N` is applied on the block `B` the force of friction between `A` and `B` is

Options

A. zero
B. 3.9 N
C. 5.0 N
D. 49 N

Answer

A

Explanation

`f_(max)` on B=80 N
`B f_(max)=80 N`
B will not slide on ground
So force =0.