Question

Escape velocity of a body of 1 kg on a planet is 100 ms–1. Gravitational potential energy of the body at the planet is = ___ J

(A) – 5000

(B) – 1000

(C) – 2400

(D) 5000

Answer 1

Correct option: (A) – 5000

Explanation:

Given : Ve = 100 m/*, m = 1 kg

Ve = √[(2GM) / R]

(100)2 = [(2GM) / R]

(GM / R) = 5000 (1)

PE = U = [(– GMm) / R]

hence from (1)

U = – 5000 m

U = – 5000 × 1J

U = – 5000 J