A block `A` with mass 100kg is resting on another block `B` of mass 200kg. As shown in figure a horizontal rope tied to a wall hold it. The coefficient of friction between `A` and `B` is `0.2` while coefficient of friction between `B` and the ground is `0.3` . the minimum required force `F` to start moving `B` will be.

Explanation

When B is tries to move, by applying a force F, then the fricitional forces acting on the blokc B are `f_(1)` and `f_(2)` with limiting values, `f_(1)=(mu_(s))_(A)m_(A)g` and `l_(2)=(mu_(s))_(B)(m_(A)+m_(B))g`
Then minimum value of F should be (for just tending to move),
`F=f_(1)+f_(2)=0.2xx100g+0.3xx300g=110g=1100N`