A block of 1 kg is stopped against a wall by applying a force F perpendicular to the wall. If `mu=0.2` then minimum value of F will be

Explanation

The stituation is shown in fig. The forces acting on the book are For book to be at rest it is essential that `mg=f_(s)`
But `f_(s"max")=mu_(s)N` and `N=F`
`because Mg=mu_(s)FrArrF=(Mg)/(mu_(s))=(1xx9.8)/(0.2)=49N`