In the track shown in figure section `AB` is a quandrant of a circle of `1` metre redius. A block is released at `A` and slides without friction until it reaches `B`. After B it moves on a rought horizontal floor and comes to rest at distance `3` meters from B. What is the coefficient of friction between floor and body?

Options

A. `1//3`
B. `2//3`
C. `1//4`
D. `3//8`

Answer

B

Explanation

`mgl = (1)/(2) mv^(2) implies u^(2) = 2g` (i)
`v^(2) = u^(2) + 2as implies 0 = 2g - 2a(3)`
`implies a = (g)/(3) implies mu_(k)g = a`
`:. mu_(k)g = (g)/(3) :. mu_(k) = (1)/(3)`