Medium MCQ +4 / -1 PYQ · JEE Mains 2022

A particle experiences a variable force $\overrightarrow F = \left( {4x\widehat i + 3{y^2}\widehat j} \right)$ in a horizontal x-y plane. Assume distance in meters and force is newton. If the particle moves from point (1, 2) to point (2, 3) in the x-y plane, then Kinetic Energy changes by :

  1. A 50.0 J
  2. B 12.5 J
  3. C 25.0 J Correct answer
  4. D 0 J

Solution

<p>$W = \int {\overrightarrow F \,.\,d\overrightarrow r }$</p> <p>$= \int\limits_1^2 {4xdx + \int\limits_2^3 {3{y^2}dy} }$</p> <p>$= [2{x^2}]_1^2 + [{y^3}]_2^3$</p> <p>$= 2 \times 3 + (27 - 8)$</p> <p>$= 25$ J</p>

About this question

Subject: Physics · Chapter: Work, Energy and Power · Topic: Work Done by a Force

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