$A$ stone dropped from a certain height takes $4$ seconds to reach the ground. The height is: (in $, m$)

The value of the gravitational constant $(G)$ depends upon:

$(a)$ Name the two factors on which the buoyant force depends.
$(b)$ State the relationship between the buoyant force on an object and the weight of the liquid displaced by it.

State the universal law of gravitation. How is the force between two bodies affected if the distance between them is tripled?

The weight of an object:

The weight of any person on the moon is about $1/6$ times that on the earth. He can lift a mass of $15\, kg$ on the earth. What will be the maximum mass,which can be lifted by the same force applied by the person on the moon (in $, kg$)?