What is the nature of motion of an object falling freely under the action of gravity?

Two bodies,one held $1 \, m$ vertically above the other,are released simultaneously and fall freely under gravity. After $2 \, s$,the relative separation of the bodies will be: (in $, m$)

The gravitational force between objects is $100 \, N$. How should the distance between these objects be changed so that the force between them becomes $50 \, N$?

$A$ stone is dropped from a cliff. Its speed after it has fallen $100 \,m$ is: (in $, m s^{-1}$)

What is the shape of the path followed by a projectile?

The mass of the planet Jupiter is $1.9 \times 10^{27} \, kg$ and that of the Sun is $1.99 \times 10^{30} \, kg$. The mean distance of the Sun from Jupiter is $7.8 \times 10^{11} \, m$. Calculate the gravitational force which the Sun exerts on Jupiter.