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Question:

The gravitational field in a region is given by →E=5N/kg^i+12N/kg^j. The change in the gravitational potential energy of a particle of mass 2kg when it is taken from the origin to a point (7m, -7m) is :

−156J

−140J

71J

13√58J

Solution:

The potential at a given point as , V =∫Edx
Thus,V=(5i+12j) ⋅(7i−7j)
V=35−84=−49
Thus, the change in potential energy is
mV=−98J