State two factors on which the value of $g$ depends.

The weight of an object at the centre of the earth of radius $R$ is

Write the expression for the acceleration due to gravity at the surface of the earth.

$A$ coin and a piece of paper are dropped simultaneously from the same height. Which of the two will touch the ground first? What will happen if they are dropped in a vacuum? Give reasons for your answer.

$A$ boy on a cliff $49\, m$ high drops a stone. One second later,he throws a second stone after the first. They both hit the ground at the same time. With what speed did he throw the second stone?

What is the acceleration due to gravity at the centre of the earth (in $m/s^2$)?