The velocity- time graph of the figure shown the motion of a wooden block of mass `1 kg` which is given an intial push at `t = 0` along a horizontal table.

Options

A. The coefficient of friction between the block and the table is `0.1`
B. The coefficient of friction between the block and the table is `0.2`
C. If the table was half of its present roughness, the time taken by the book to complete the journey is `4 s`
D. If the table was half of its present roughness, the time taken by the book to complete the journey is `8 s`

Answer

A, D

Explanation

`a = "slop of" v = t "graph"`
`= - 1 m//s^(2)`
`:. "Retardation" = 1 m//s^(2) = (mu mg)/(m) = mu g`
or `mu = (1)/(g) = (1)/(10) = 0.1`
If `mu`is half ,then reladation a is also half .So using
`v =u - at`
or `0 = u - at`
or `t = (u)/(a)` or `t prop (1)/(a)`
we can see that `t` will be two times.