Question

A block slides down an incline of 30°with the horizontal. Starting from rest it covers 8m in the first 2 seconds. Find the coefficient of kinetic friction between the two.

Answer 1

Force acting along the inclination is = mgsinΘ  - μmgcosΘ

so acceleration a =(mgsinΘ  - μmgcosΘ)/m

                         =gsinΘ  - μgcosΘ

S =ut +1/2 a t2  

8=0+1/2 (gsinΘ  - μgcosΘ)*4

or 4=10*1/2  - μ*10*√3/2

  μ=1/5√3

Answer 2

the coefficient of kinetic friction between the two.