JEE Main 2018PhysicsLaws of MotionMediumMCQ

JEE Main 2018 — Laws of Motion Question with Solution

JEE Main 2018 (15 Apr)

Question

A given object takes n times more time to slide down a 45o rough inclined plane as it takes to slide down a perfectly smooth 45o incline. The coefficient of kinetic friction between the object and the incline is:

Choose an option

Show full solutionCorrect option: B
Correct answer
B1-1n2

Step-by-step explanation

Time taken to slide along a smooth surface is t1.
S=12gsin⁡45ot12
t1=22sg
Time taken to slide along a rough surface is t2.
S=12gsin⁡45o-μgsin⁡45o t22
t2=22sg1-μ
t2=nt1
22sg1-μ=n2×22sg⇒1-μ=1n2⇒μ=1-1n2

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About this question

This is a previous-year question from JEE Main 2018, covering the Laws of Motion chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.