In the arrangement shown in figure , there is friction between the blocks of masses m and 2m which are in contact . The ground is smooth . The mass of the suspended block is m . The block of mass m which is kept on mass 2m is stationary with respect to block of mass 2 m . The force of friction between m and 2 m is (pulleys and string are lig frictionless ) :

Options

A. `(mg)/(2)`
B. `(mg)/(sqrt2)`
C. `(mg)/(4)`
D. `(mg)/(3)`

Answer

C

Explanation

`mg - T = ma " " ……. (i)`
`T = 3ma " " ……. (ii)`
Adding Eqns. (i) and (ii)
`a= g/4`
f = ma