The pilot of a plane measures an air velocity of 165km/h south relative to the plane. an observer on
the ground sees the plane pass overhead at a velocity of 145 km/h toward the north. what is the
velocity of the wind that is affecting the plane relative to the observer?

The speed obtained by the pilot is not accurate since it is measuring the rate of travel in the wind, true velocity is that compared to the ground. Therefore the speed of the wind is:

v wind = 165 - 145

v wind = 20 km/h

Therefore the wind velocity = 20 km/h against the plane.

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.