Question

The value ofthe gravitational field in a region is given by g = 2i + 3j. What is the change in gravitational potential energy of a particle of mass 5kg when it is taken from the origin O(0,0) to a point P(10, -5)? (Letters in bold are vectorial representations)

(a) 5 J

(b) 10 J

(c) 25 J

(d) 50 J

This question was addressed to me in semester exam.

I need to ask this question from Gravitational Potential Energy topic in division Gravitation of Physics – Class 11

Answer 1

Right option is (c) 25 J

Explanation: The gravitational potential energy, in vectorial mathematics, is the dot product of the gravitational field and relative position multiplied by mass.

Gravitational potential energy = (g . P) x m

 = [(2i + 3j) .(10i – 5j)] x 5

 = (20 – 15) x 5

 = 25 J.