Question

A block of mass `1kg `is placed on a rough horizontal surface. A spring is attached to the block whose other end is joined to a rigid wall, as shown in the figure. A horizontal force is applied on the block so that it remains at rest while the spring is elongated by `x(x ge (mumg)/(k))`. Let `F_(max)` and `F_(mi n)` be the maximum and minimum values of force `F` for which the block remains in equilibrium. For a particular `x, F_(max)-F_(mi n)=2N`. Also shown is the variation of `F_(max)+F_(mi n)` versus `x`, the elongation of the spring.

The coefficient of friction between the block and the horizontal surface is `:`
A. `0.1`
B. `0.2`
C. `0.3`
D. `0.4`

Answer 1

Correct Answer - A
`F_(max)=kx+mu mg`
`F_(min)=kx-mu mg`
`:. F_(max)-F_(min)=2mu mg`
or `2=2mu 10`
`:. M=0.1`