What is the name given to the path followed by a projectile?

If gravitation is the power by which all bodies tend towards each other,then why do all bodies tend towards the centre of the earth?

Define free fall.

$A$ ball is dropped from a height of $20\, m$. $A$ second ball is thrown downwards from the same height after one second with initial velocity $u$. If both the balls reach the ground at the same time, calculate the initial velocity of the second ball. (Take $g = 10\, m s^{-2}$).

State any two properties of gravitational force.

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