A block of mass 1 kg is pushed against a rough vertical wall of `mu=0.1`

For F = 150, 50 or 100 N the force of friction on the blocks is respectively :

Options

A. 10 N ,5 N , 10 N
B. 15 N ,5 N , 10 N
C. 10 N ,10 N , 10 N
D. none of these

Answer

a

Explanation

F=N `rarr` mg `le N mu` to avoid sliding i.s `f ge mg//mu` ie `f ge 100 N` to avoid sliding if there is no sliding f=mg
i.e if `f ge 100 N` force offriction =mg & for `f lt 100` N sliding occurs and kinetic friction acts `rarr f=muN=muF`