RE-NEET2026Physics-Mechanics

RE-NEET 2026 Physics Work and Energy MCQ Question

Type: MCQ-numerical-Hard

A particle of mass M moves along a horizontal x axis from x=0 to x=L. The coefficient of kinetic friction varies as a function of x as μₖ(x) = μ₀ - αx, where μ₀, α are constants of appropriate dimensions, so that μₖ(L) = 0. The total work done by the frictional force during the motion is ημ₀MgL, where g is the acceleration due to gravity. The value of η is:

A

1

B

1/3

C

1/2

D

3

Correct Answer

Option B

Detailed Explanation

Integrating the frictional force over the distance gives the work done as ημ₀MgL, where η = 1/3.

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