A ball falls from a tower a) The two forces acting on the tennis ball are equal and opposite. What is the resultant force
?acting on the ball

Zero

Explanation:

The resultant force acting on the ball would be zero.

Since only two forces were acting on the tennis ball and these forces negate and cancel each other in magnitude, the resultant effect on the tennis ball would be zero.

Assuming that one of the forces is 5N and acting from the positive side and the other force is also 5N but acting from the negative side.

Resultant = -5 + 5 = 0 N

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.