Two blocks A and B of masses `2 kg` and `8 kg` respectively are kept in contact and pressed against a roguh vertical wall by applying a horizontal force `F = 50 N` as shown, The frictional force acting between the two blocks is

Options

A. zero
B. `6 N`
C. `8 N`
D. `10 N`

Answer

B

Explanation

The two block will move with a common acceleration
`a = (100- 30)/(10) = 7 m//s^(2)`
Now, for the block 'A'
`20 - f_(S) = 2 xx 7`
`therefore f_(S) = 6N`