Answer
a) From the child's point of view range remains the same for the front and rear parts of the car.
b) From the point of view of an observer standing still on the ground the range is greater on the front side than the rear side.
Work Step by Step
a) Child is seating in the RV car which is moving with constant velocity $\text{v}$ So, the child is moving with the same velocity (i.e. $\text{v}$).
When the cannon is fired toward the front or the rear of the RV in the child's point of view, the velocity of the car does not get added or get subtracted from the velocity of the cannon fired.
So, From a child's point of view, the range toward the rear or front remains the same.
b)Now, In the case of the point of view of an observer standing still on the ground the velocity (i.e $\text{v}$) of the car affects the range of the cannon fired.
In case when the cannon is fired in the rear direction of the RV car
the velocity of the car get subtracted from the velocity of the cannon
i.e $V_{res} = V_{car} - V{cannon}$.
$\therefore \text{Range decreases}$
In the case of Front
the velocity of the car get added to the velocity of the cannon
i.e $V_{res} = V_{car} + V{cannon}$.
$\therefore \text{Range increases}$
