Question

What is the escape velocity for a body on the surface of a planet on which the acceleration due to gravity is (3.1)² m/s² and whose radius is 8100 km?

(a) 2790 km/s

(b) 27.9 km/s

(c) \(\frac{27.9}{\sqrt 5}\) km/s

(d) 27.9√5 km/s

Answer 1

Correct option is (b) 27.9 km/s

Escape velocity, v = \(\sqrt {2gR}\)

\(= \sqrt{2 \times (3.1)^2 \times 8100 \times(10)^3}\)

\(= 27. 9 km/s\)