Two block `A` and `B` are separted by some distance and tied by a string as shown in the figure . The force of friction in both the block at `t = 2 s` is

Options

A. `4 N(rarr), 5 N(larr)`
B. `2 N(rarr), 5 N(larr)`
C. `0 N(rarr), 10 N(larr)`
D. `1 N(larr), 10 N(larr)`

Answer

D

Explanation

`(f_(1))_(max) = mu_(1) m_(1) g = 6 N`
`(f_(2))_(max) = mu_(2) m_(2) g = 10 N`
At `t = 2 s, F' = 4 N`
Net pulling force , `(f_(1))_(max) = F' - F' = 11 N`

Total maximum resisting force ,
`F_(2) = (f_(1))_(max) + (f_(2))_(max) = 16 N`
Since `F_(1) lt F_(2)`, system will not move and free body diagrams of the two block are as shown in figure