Two smooth block are placed at a smooth corner as shown in fig. Both the bloks are having mass m. We apply a force F on the block m. Block A presses block B in the normal direction, due to which pressing force on vertical wall will increase, and pressing force on the horizontal wall decreases, as we increases `F(theta = 37^(@)` with horizontal).

As soon as the pressing force on the horizontal wall by block B become zero, it will lose contact with ground. If the value of F further increases, block B will accelerate in the upward direction and simulaneously block A will towards right.
What is the minimum value of F to lift block B from ground?

Options

A. `25/12` mg
B. `5/4` mg
C. `3/4` mg
D. `4/3` mg

Answer

C

Explanation

`N cos 37^(@)=mg`
`N=(5mg)/4`
Now, `N_(H)=Nsin 37^(@)=(5mg)/4xx3/5=F`