1-mavzu: kirish. Mexanika bo’limlari. I-mashg’ulotning maqsadi

Energiyaning saqlanish qonuni.
Yopiq sistemadagi barcha hodisalarda to’la energiya hech qachon bordan yo’q bo’lmaydi, yo’qdan bor bo’lmaydi, ya’ni to’la energiya qiymati o’zgarmasdan saqlanadi . Energiya jismlar o’zaro kuch bilan ta’sirlashganda jismlarni qizdirishga sarf bo’ladi. To’la energiya yopiq sistemada konstantadir.
Energiya miqdori o’zgarmay qoladi, faqatgina bir turdan ikkinchi turga o’tishi mumkin.
Conservation of Energy
In physics, a conserved quantity is something that you wouldn’t be able to get rid of even if you wanted to. Conservation laws in physics always refer to a closed system, meaning a region of space with boundaries through which the quantity in question is not passing. In our example, the alchemist’s laboratory is a closed system because no gold is coming in or out through the doors.
The Law of Conservation of
Energy
It is possible to give a numerical rating, called energy, to the state of a physical system. The total energy is found by adding up contributions coming from characteristics of the system such as motion of objects in it, heating of the objects, and the relative positions of objects that interact via forces. The total energy of a closed system always remains constant. Energy cannot
be created or destroyed, but only transferred into or out of a system. ⁷[8]
Berk ( yopiq ) sistemadagi jismning to’la energiyasi uning kinetik va potensial energiyalarining yig’indisiga teng va o’zgarmas bo’ladi:
EE_kin  E_pot (6.7) Bu ifoda energiyaning saqlanish qonuni deyiladi.
Qattiq jism harakati
Jismni ixtiyoriy harakatini ko’rganda uni ikki asosiy harakat — ilgarilanma va aylanma harakatlarning yig’indisi sifatida qarash mumkin, ya’ni umumiy ko’chish:

SS_ilg  S_ayl . (7.1)

Kattiq jismning bunday harakatini yassi harakat deyiladi. SHunga ko’ra qattiq jism tezligini shunday yozish mumkin:

V V_ilg  V_ayl , (7.2)

bu yerda – V_ilg ,V_ayl ilgarlanma va aylanma harakat tezligi. Aylanish jarayonida har xil nuqtalarda har xil bo’ladi:

V_ayl R , (7.3)

bu yerda  - burchak tezlik, R - nuqtaning radius-vektori. Demak, qattiq jismning murakkab harakatining tezligi shunday bo’ladi:

VV_ilg R . (7.4)

Qattiq jism qo’zg’almas o’q atrofida aylanganda uning harakati uchun Nyutonning 2-qonunini tadbiq etish mumkin. Buning uchun qattiq jismning aylanma harakatini xarakterlaydigan ikki fizik kattalik—kuch momenti M va inersiya momenti I kiritiladi.

1. 
   If the boat is cruising at constant speed, then the forces are all presumably
   

constant, so Fd is correct.

2. 
   The force is changing: weaker at first, and stronger as the magnet
   

approaches the fridge. Fd would give the wrong answer.

3. 
   Gravity is getting weaker and weaker and the probe The momentum of a
   

material object, i.e. a piece of matter, is defined as p=mv , the product of the object’s mass and its velocity vector.
The units of momentum are kg^.m/s, and there is unfortunately no abbreviation for this clumsy combination of units.
The reasoning leading up to the definition of momentum was all based on the search for a conservation law, and the only reason why we bother to define such a quantity is that experiments show it is conserved: