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

Answer 1

Correct Answer - A
(a) Given, initial velocity =v
Final velocity =0
coefficient of friction =`mu`
For a straight line motion , v-u=at
Here, `0-v=-(mu g)t" "(as,a=(mu mg)/(m))`
Negative sign indicates retardation.
`therefore" " t=(v)/(mu g)`