State whether the following statement is true or false:
The force of attraction between two bodies is called gravity.

$A$ stone is dropped from the edge of a roof.
$(a)$ How long does it take to fall $4.9 \, m$?
$(b)$ How fast does it move at the end of that fall?
$(c)$ How fast does it move at the end of $7.9 \, m$?
$(d)$ What is its acceleration after $1 \, s$ and after $2 \, s$?

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 $, kg$)?

Show that if the earth attracts two bodies $A$ and $B$ placed at the same distance from the centre of the earth with the same force,then their masses are equal.

What is meant by acceleration due to gravity? Suppose a planet exists whose mass and radius both are half of that of Earth. Calculate the acceleration due to gravity on the surface of this planet.

What is meant by free fall?