How does acceleration due to gravity depend on the mass of the planet?

$(a)$ What do you mean by free fall?
$(b)$ What happens to the direction of motion of objects during free fall?
$(c)$ $A$ stone is dropped from a height of $19.6 \, m$. Calculate:
$(i)$ Time taken to fall.
$(ii)$ How fast does it move at the end of this fall?
$(iii)$ Acceleration after $1 \, s$.

The acceleration due to gravity at the moon's surface is $1.67 \, m s^{-2}$. If the radius of the moon is $1.74 \times 10^{6} \, m$,calculate the mass of the moon. (Use $G = 6.67 \times 10^{-11} \, N m^{2} kg^{-2}$)

$A$ stone is allowed to fall from the top of a tower $100 \, m$ high and at the same time another stone is projected vertically upwards from the ground with a velocity of $25 \, m s^{-1}$. Calculate when and where the two stones will meet? (Take $g = 10 \, m s^{-2}$).

The mass of a girl is $50\, kg$. What will be her approximate weight on the Earth? How will her mass and weight change on the surface of the Moon?

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