Question 10.
Solve the following example.
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 on B is half that of its value on A?
Answer:
We know that acceleration due to gravity (g) is given by
Where G = universal gravitational constant;
M = mass of the planet;
R = radius of the planet;
Mass of Planet A = MA;
Radius of Planet A = RA;
Value of ‘g’ on A = gA;
Mass of Planet B = MB;
Radius of Planet B = RB;
Value of ‘g’ on B = gB;
Also it is given that;
Therefore;
(from question 
)
⇒ 
Therefore the mass of planet B should be two times the mass of planet A i.e MB = 2MA .
