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NEETPhysicsLaws of Motion

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In an Atwood machine consisting of two unequal masses connected by a light string over a smooth pulley, the tension in the string is greater than the weight of the heavier mass and less than the weight of the lighter mass. Reason (R): The heavier mass accelerates downwards, meaning the net force on

Options

  1. ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
  2. BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
  3. C(A) is correct but (R) is not correct
  4. D(A) is not correct but (R) is correct

Correct answer

D. (A) is not correct but (R) is correct

Step-by-step solution

Let the heavier mass be m₁ and the lighter mass be m₂ . For the heavier mass m₁ , it accelerates downwards. The equation of motion is: m₁g - T = m₁a T = m₁(g - a) This shows that the tension T is strictly less than the weight of the heavier mass ( T For the lighter mass m₂ , it accelerates upwards. The equation of motion is: T - m₂g = m₂a T = m₂(g + a) This shows that the tension T is strictly greater than the weight of the lighter mass ( T > m₂g ). Therefore, Assertion (A) is incorrect. Reason (R) correctly states

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