Question

The radius of planet A is half the radius of planet B if the mass of A is Ma what must be the mass of B so that the value of g in B is half that of its value on A?

Answer 1

The radius of Planet A is half of the Planet B.

Let the radius of planet B=r

Then the radius of planet A = r/2

The mass of Planet A =Ma

For what mass of planet B the value of g in planet B is half of the value of g on planet A.

Mass of planet B =?

Formula for g is

g=GM/R^2

g on planet A ,ga=GMa/(r/2)^2

=GMa/(r^2/4)

=4GMa/r^2

g on planet B ,gb=G?/r

According to question,

gb=ga/2

G?/r=4GMa/2r

?=2Ma

Hence mass of Planet B =2Ma

Answer 2

Answer:

The mass of planet B must be twice that of the planet A.

Explanation:

See the attachment.