A satellite orbits planet X with a speed at a distance from the centre of planet X

PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

A satellite orbits planet X with a speed

v_X

at a distance

r

from the centre of planet X. Another satellite orbits planet Y at a speed of

v_Y

at a distance

r

from the centre of planet Y. The mass of planet X is

M

and the mass of planet Y is

4M

. What is the ratio of

\frac{v_X}{v_Y}

? (A) 0.25 (B) 0.5 (C) 2.0 (D) 4.0