Supposing Newton’s law of gravitation for gravitation forces F₁ and F₂ between two masses m₁ and m₂ at positions r₁ and r₂ read F₁ = - F₂ = GM₀² r where M₀ is a constant of dimension of mass, r₁₂ = r₁ – r₂ and n is a number. In such a case,

Given:

Where

= constant

For calculating acceleration due to gravity let

M₁ = Mass of earth = M

M₂ = mass of object

= radius of earth = R

Then magnitude of force between the object and earth is given by

Which can be said as

Where K is a constant

Therefore, acceleration due to gravity can be calculated as

Which depends on mass and hence different for different objects

Therefore (a) is the correct option

since this force follows inverse square law, hence Kepler’s first two are valid but since g is no longer constant, therefore Kepler’s third law (Law of periods) does not remain valid

therefore (c) is the correct option

when n is negative than force is given by

Where a = - n

Therefore, force is inversely proportional to mass of body, hence an object lighter than water will experience more force than water and therefore will sink in water

Therefore (a), (c) and (d) are the correct options