Question

A block `B` is pushed momentarily along a horizontal surface with an initial velocity `v` . If mu is the coefficient of sliding friction between `B` and the surface, block `B` will come to rest after a time:

A. `(v)/(mu g)`
B. `(vg)/(mu)`
C. `(v mu)/(g)`
D. `(mu g )/(v)`

Answer 1

Correct Answer - A
Given , initial velocity = v
Final velocity = 0
Coefficient of fraction = `mu`
For a straight line motion
`v - u = at`
Here ` 0 - v = - (mu g) t " " [ As mu = (a)/(g)]`
Negative sign indicates retardation
`implies t = (v)/(mu g)`