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JEE Main 20202 SeptemberMorning Shift
Exam
JEE Main
Year
2020
Date
2 September
Shift
Morning Shift
Subject
Physics
Chapter
Laws of Motion

JEE Main 2020 · 2 September · Morning Shift · Physics · Laws of Motion

A small block starts slipping down from a point B on an inclined...

A small block starts slipping down from a point BB on an inclined plane ABAB, which is making an angle θ\theta with the horizontal section BCBC is smooth and the remaining section CACA is rough with a coefficient of friction μ\mu. It is found that the block comes to rest as it reaches the bottom (point A) of the inclined plane. If BC=2ACBC = 2AC, the coefficient of friction is given by μ=ktanθ\mu = ktan \theta. The value of kk is .......

A small block starts slipping down from a point B on an inclined plane AB , which is making an angle θ with the

Correct answer

0

Step-by-step solution

Let AC=ℓ∴BC=2ℓ∴AB=3ℓAC = ℓ ∴ BC = 2ℓ ∴ AB = 3ℓ

A small block starts slipping down from a point B on an inclined plane AB , which is making an angle θ with the

Apply work – Energy theorem

Wt+Wmg=\DeltaKE{W}_{t} + {W}_{mg} = \DeltaKE

mg(3ℓ)sinθ−μmgcosθ(ℓ)=0+0mg ( 3ℓ ) sin\theta - \mu mg cos\theta ( ℓ ) = 0 + 0

μmgcosθℓ=3mg/sinθ\mu mgcos\thetaℓ = 3mg / sin\theta

μ=3tanθ=ktanθ\mu = 3tan\theta = ktan\theta

k=3k = 3

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