here we know that ball will drop down by total distance 3.2 m
so here we know that
now using kinematics
now in the same time it will cover horizontal distance of 0.75 m
so speed of the ball will be
there is no change in the electric potential energy as it is in rest on both conditions.
russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.
if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have
where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that
so that the position function is
which means the velocity is
then the total distance traveled is
so the total distance traveled is 20 m.
on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.