$(a)$ 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 $1 \, s$.

(N/A) Free fall is the motion of an object falling solely under the influence of gravitational force,with constant acceleration.
$(b)$ The direction of motion remains the same (vertically downwards) during free fall.
$(c)$ Given: Initial velocity $u = 0 \, m/s$,height $h = 19.6 \, m$,acceleration $g = 9.8 \, m/s^2$.
$(i)$ Using the equation of motion $h = ut + \frac{1}{2}gt^2$:
$19.6 = 0 + \frac{1}{2} \times 9.8 \times t^2$
$19.6 = 4.9 \times t^2$
$t^2 = 4$
$t = 2 \, s$.
$(ii)$ Using the equation $v = u + gt$:
$v = 0 + 9.8 \times 2$
$v = 19.6 \, m/s$.
$(iii)$ Since the object is in free fall,the acceleration is constant and equal to the acceleration due to gravity,which is $9.8 \, m/s^2$ at any time,including after $1 \, s$.