The value of the quantity $G$ in the law of gravitation:

$(i)$ Why is Newton's law of gravitation called the universal law?
$(ii)$ What is the significance of this law in nature?

$A$ 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?

Why does a body weigh more at the poles than at the equator?

$A$ stone is thrown vertically upwards with a velocity of $40 \, m s^{-1}$ and is caught back. (Taking $g = 10 \, m s^{-2}$) Calculate the maximum height reached by the stone. What is the net displacement and total distance covered by the stone?

Why is the value of $g$ greater at the poles than at the equator?