A body takes just twice the time as long to slide down a plane inclined at 30o to the horizontal as if the plane were frictionless. The coefficient of friction between the body and the plane is

(1) 34

(2) 3

(3) 43

(4) 34

Concept Videos :-

#16-Static-Friction-Force
#17-Solved-Examples-8
#18-Solved-Examples-9
#19-Solved-Examples-10
#20-Kinetic-Friction-Force
#21-Solved-Examples-11

Concept Questions :-

(1)

When the plane is smooth:t=2la=2lgsin300when the plane is rough:t'=2la'=2lgsin300-μgcos300Now, t'=2t2lgsin300-μgcos300=2×2lgsin3002lgsin300-μgcos300=4×2lgsin300gsin300-μgcos300=gsin3004μcos300=38μ=34 

Difficulty Level:

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