A block of mass `m` is released from point (A) in figure. The track is frictionless except for the position between points (B) and (C), which has a length of `d_(BC)`. The block travels down the track, hits a spring of force constant `k`, and compresses the spring x from its equilibrium position before coming at rest momentarily. Determine the coefficient of kinetic friction between the block and the rough surface between (B) and (C).

Explanation

`Delta_(mech)=-fdximpliesE_f-E_i=-f*d_(BC)`

`1/2kx^2-mgh=-mumgd_(BC)`
`mu=(mgh-1/2kx^2)/(mgd_(Bc))`