What is melting? when an ice cube turns from a solid to a liquid, the particles

Melting is the breaking of bonds between particles (atoms) due to the increase in temperature (energy).

Explanation:

When elements are in solid form, it means that the conditions they are in do not allow particles to move much, which creates stable bonds (stable bonds as in, difficult to break) between atoms.  

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When the temperature increases, this atoms gain more and more energy (which makes them move) until bonds break and the transition from solid to liquid begins.

Hope it helped,

BioTeacher101

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.