JEE Main & Advanced Physics Gravitation / गुरुत्वाकर्षण Question Bank Self Evaluation Test - Gravitation

  • question_answer
    The gravitational field in a region is given by\[\vec{g} =5N/kg\hat{i}+12N/kg\hat{j}\]. The change in the gravitational potential energy of a particle of mass 1 kg when it is taken from the origin to a point \[(7m,-3m)\] is:

    A) \[71\text{ }J\]

    B) \[13\sqrt{58}J\]

    C) \[-71\text{ }J\]

    D) \[1\text{ }J\]

    Correct Answer: D

    Solution :

    [d] Gravitational field, \[I=\left( 5\hat{i}+12\hat{j} \right)\text{ }N/kg\] \[I=\frac{dv}{dr}\] \[v=-\left[ \int\limits_{0}^{x}{{{I}_{x}}dx+\int\limits_{0}^{y}{{{I}_{y}}dy}} \right]=-[{{I}_{x}}.x+{{I}_{y}}.y]\] \[=-\left[ 5\left( 7-0 \right)+12\left( -3-0 \right) \right]\] \[=-\left[ 35+\left( -36 \right) \right]=1\operatorname{J}/kg\] i.e., change in gravitational potential 1 J/kg. Hence change in gravitational potential energy 1J


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