As shown in figure, `A` is a man of mass `60 kg` standing on a block `B` of mass `40 kg` kept on ground. The coefficient of friction between the feet of the man and the block is `0.3` and that between `B` and the ground is `0.2` . If the person pulls the string with `125 N` force ,then

Options

A. `B` will slideon ground
B. `A and B` will move with acceleration `0.5 ms^(-2)`
C. the force of friction acting between `A and B` will be `125 N`
D. the force of friction acting between ` B` and ground will be `250 N`

Answer

C, D

Explanation

Maximum force of friction between `A and B`
`(f_(1))_(max) = 0.3 xx 60 xx 10 = 180 N`
Maximum force of friction between `B` and ground
`(f_(2))_(max) = 0.3 xx (60 + 40) g = 300 N`

Both are stationary
`f_(1) = T = 125 N`
`f_(2) = T + f_(1) = 250 N`