What do we call the gravitational force between the earth and an object?

$A$ ball thrown up vertically returns to the thrower after $6\, s$. Find
$(a)$ the velocity with which it was thrown up,
$(b)$ the maximum height it reaches,and
$(c)$ its position after $4\, s$.

$A$ stone is released from the top of a tower of height $19.6\, m$. Calculate its final velocity just before touching the ground. (in $, ms^{-1}$)

What do you mean by buoyancy?

You have a bag of cotton and an iron bar,each indicating a mass of $100\, kg$ when measured on a weighing machine. In reality,one is heavier than the other. Can you say which one is heavier and why?

The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with which the moon attracts the earth? Why?