Question

There are two planets: Planet A and Planet B. Both planets are the same size but Planet B is twice the mass of Planet A. Which one would you expect to have a stronger pull gravity on its surface? Explain. *

Answer 1

Answer:

Planet B

Explanation:

The strength of the gravitational field on the surface of a planet is given by the equation:

$g=\frac{GM}{R^2}$ (1)

where:

G is the gravitational constant

M is the mass of the planet

R is the radius of the planet

In this problem, we have two planets, A and B.

The two planets have same radius, R, while they have different masses, in particular

$M_B=2M_A$

So, the mass of planet B is twice the mass of planet A.

Looking at the eq.(1), we see that the gravitational field strength is proportional to the mass of the planet: therefore, the larger the mass, the greater the field strength.

So, since planet B has larger mass, then its gravity will be stronger than planet A.