15. If the mass of 1 object decreases, what will happen to the gravitational force for that object?

Let us consider the two bodies of masses m1 and m2 separated by some distance in a vacuum. The force of attraction (gravitational force ) is given

F=Gm1m2r2——(1)

Where,

G= is a universal gravitational constant.

r= distance of separation.

Now if the mass of the one object is halved then the force is given by

F1=G(m12)m2r2

⇒F1=Gm1m22r2

⇒F1=12×Gm1m2r2

⇒F1=12F[from equation (1)]

⇒F1=0.5F.

Therefore the magnitude of the new force is half of the original force/old force.

the answer is a. hope this .