Oil having a density of 928 kg/m' floats on
water. A rectangular block of wood 4.06 cm
high and with a density of 979 kg/m” floats
partly in the oil and partly in the water. The
oil completely covers the block.
How far below the interface between the
two liquids is the bottom of the block?
Answer in units of m.

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

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.

snell's law

refractve index = sin incidence / sin refraction