Q.

The time taken by an object to slide down a 45° rough inclined plane is n times as it takes to slide down a perfectly smooth 45° inclined plane. The coefficient of kinetic friction between the object and the inclined plane is               [2023]

1 11-n2  
2 1-1n2  
3 1+1n2  
4 1-1n2  

Ans.

(4)

a1=gsinθ=g2

a2=gsinθ-Kgcosθ=g2-Kg2

t2=nt1 and a1t12=a2t22

g2t12=(g2-Kg2)n2t12

  K=1-1n2