Question

Find coefficient of kinetic friction if a body of mass 'm' starts to on a plane with angle of inclination 30degrees. the body moves 4meters in 4second.

Answer 1

Effective force acting on the body downward along the inclined plane with angle of inclination 30° is

F = mgsin30°-umgcos30°,where u is the coefficient of kinetic friction.

So acceleration

a=F/m=gsin30°-ugcos30°

Again the body traverses 4 m in 4sec starting from rest

So 4=1/2×a×4²

Or,a==0.5m/s²

Hence

0.5=gsin30°-ugcos30°

=>1=g-ug×√3

=>u =(10-1)/(10√3)=3√3/10==0.52