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Work Power and Energy question

2022 · 25 Jun · Shift 1 · Q62
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Work Power and Energy question

2022 · 25 Jun · Shift 1 · Q62

JEE MainPhysicsWork Power and EnergyNumerical+4 / −1
A uniform chain of 6 m length is placed on a table such that a part of its length is hanging over the edge of the table. The system is at rest. The co-efficient of static friction between the chain and the surface of the table is 0.5, the maximum length of the chain hanging from the table is ‾\underline{\hspace{2cm}}​ m.
Numerical answer
View written solutionFree

Correct answer: 2

  1. Let the hanging length be xxx m

    Total length of chain =6= 6=6 m.

    So, length on the table =6−x= 6-x=6−x m.

  2. Forces acting on the chain

    Since the chain is uniform, let its mass per unit length be λ\lambdaλ.

    • Weight of hanging part pulls the chain downward: Fpull=λxgF_{\text{pull}} = \lambda x gFpull​=λxg

    • The part lying on the table experiences friction.

      Normal reaction on the portion on table: N=λ(6−x)gN = \lambda (6-x) gN=λ(6−x)g

      Maximum static friction: fmax⁡=μsN=0.5 λ(6−x)gf_{\max} = \mu_s N = 0.5\,\lambda (6-x) gfmax​=μs​N=0.5λ(6−x)g

  3. Condition for maximum hanging length at rest

    For the chain to be just on the verge of slipping, λxg=0.5 λ(6−x)g\lambda x g = 0.5\,\lambda (6-x) gλxg=0.5λ(6−x)g

    Cancel λg\lambda gλg from both sides: x=0.5(6−x)x = 0.5(6-x)x=0.5(6−x)

  4. Solve for xxx

    x=3−0.5xx = 3 - 0.5xx=3−0.5x 1.5x=31.5x = 31.5x=3 x=2x = 2x=2

  5. Final answer

    The maximum length of the chain hanging from the table is 2 m\boxed{2\text{ m}}2 m​

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