Fizika asoslari darsliklari

Qaytmas termodinamik jarayonlarni tushuntirish uchun olimlar termodinamikaning ikkinchi qonunini tuzdilar. Termodinamikaning ikkinchi qonuni koinotda qanday jarayonlar sodir bo'lishi mumkinligini va qaysi jarayonlar sodir bo'lmasligini tushuntiradi. RJE Klauzius (1822-1888) ismli bir olim quyidagi bayonotni berdi:

Tabiiyki, issiqlik yuqori haroratli narsalardan past haroratli narsalarga o'tadi; tabiiyki, issiqlik past haroratli narsalardan yuqori haroratli narsalarga o'tmaydi (Termodinamikaning ikkinchi qonuni - Klauziyning bayonoti).

Klauziyning bayonoti termodinamikaning ikkinchi qonunining maxsus bayonotlaridan biridir. U maxsus bayonot deb ataladi, chunki u faqat bitta jarayonga, ya'ni issiqlik uzatishga tegishli. Bu bayonot boshqa jarayonlar bilan bog'liq bo'lmaganligi sababli, bizga umumiyroq bayonot kerak. Termodinamikaning ikkinchi qonunining umumiy bayonotini ishlab chiqish issiqlik dvigatellarini o'rganishga asoslangan. Shuning uchun biz avval dvigatel issiqligini muhokama qilamiz.

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Article Thermodynamic processes : Isothermal Adiabatic Isochoric Isobaric

There are four thermodynamic processes, namely Isothermal, isochoric, isobaric and adiabatic processes.

Isothermal Process (constant temperature)

In an isothermal process, system temperature is kept constant. Theoretically, the analyzed system is an ideal gas. Ideal gas temperature is directly proportional to ideal internal gas energy (U = 3/2 n R T). T does not change, so U also does not change. Thus, if applied to the isothermal process, the first law of the thermodynamic equation becomes:

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Thermodynamic process

Heat (Q) is the energy that moves from one object to another because of the temperature difference. About systems and environments, heat is energy moving from system to environment or energy moving from environment to system, due to the temperature difference. If the system temperature is higher than the ambient temperature, heat will flow from the system to the environment. If the ambient temperature is higher than the system temperature, then heat flows from the environment to the system.

Heat (Q) is energy that moves due to the temperature difference, whereas work (W) is related to energy transfer through work. For example, if the system does work on the environment, then energy moves from system to environment. Conversely, if the environment does work on the system, then energy moves from environment to system.

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Noelastik to'qnashuvlar

The conservation of kinetic energy law is not applicable in inelastic collisions. The conservation of momentum law is applicable in inelastic collisions if only no external force acts on the two colliding objects. In an inelastic collision, two objects stick together or are attached to each other after the collision.

1-misol savol.

Two objects are of the same mass, namely 1 kg. Object 1 moves on a flat plane at a speed of 10 m/s and collides with object two which is at rest. After the collision, the two objects stick together. What is the speed of the two objects after the collision?

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Qisman elastik to'qnashuvlar

Qisman elastik to'qnashuvlarda impulsning saqlanish qonuni qo'llaniladi, kinetik energiyaning saqlanish qonuni esa qo'llanilmaydi. To'qnashuv sodir bo'lganda, kinetik energiyaning bir qismi tovush energiyasiga, issiqlik energiyasiga va ichki energiyaga aylanadi. Elastik so'zining ishlatilishi to'qnashuvdan keyin ikki jism bir-biriga yopishib qolmasligini, balki sakrab tushishini anglatadi.

Qisman elastik to'qnashuvga misol qilib ikkita marmar yoki ikkita bilyard to'pining bir o'lchovli to'qnashuvini keltirish mumkin.

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Chiziqli impulsning saqlanishi

Chiziqli impulsning saqlanish qonunida aytilishicha, agar ikkita to'qnashayotgan jismga tashqi kuch ta'sir qilmasa, to'qnashuvdan oldingi jismlarning impulsi to'qnashuvdan keyingi jismlarning impulsiga teng bo'ladi.

p₁ +p₂ =p₁ ' + p₂ ' ……………….. 1.4-tenglama

m₁ v₁ +m₂ v₂ = m₁ v₁ ' + m₂ v₂ "

Agar to'qnashuvdan keyin ikkala jism ham bir-biriga yopishib qolsa,

m₁ v₁ +m₂ v₂ = (m₁ +m₂ ) v'

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Mutlaqo elastik to'qnashuvlar

A collision of two objects is called a perfectly elastic collision if the momentum or kinetic energy of each object before the collision is equal to the momentum and kinetic energy of each object after the collision. In other words, the conservation of momentum law and conservation of kinetic energy law are applicable in perfectly elastic collisions. The use of the word elastic signifies that after the collision, the two objects do not stick together or are not attached to each other but bounce off. The momentum of each object is conserved.

The momentum of each object is conserved.

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Ish-mexanik energiya printsipi

Ish-kinetik energiya teoremasi shuni ko'rsatadiki, sof ish yoki sof kuch tomonidan bajarilgan ish kinetik energiyaning o'zgarishiga teng.

W_to'r = TO_t – TO_o = 1⁄2 m(v)_t² - v_o²)

W_to'r = Ikki xil kuch mavjud, ya'ni konservativ kuch va konservativ bo'lmagan kuch. Shunday qilib, to'r ishi konservativ kuch tomonidan bajarilgan ish va konservativ bo'lmagan kuch tomonidan bajarilgan ishdan iborat deb hisoblash mumkin.

W_c + Vt_nc = ΔKE

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Konservativ kuchlar tomonidan bajarilgan ish Potensial energiya

Vertikal yuqoriga qarab harakatlanadigan va keyin maksimal balandlikka yetgandan so'ng dastlabki holatiga qaytadigan jismni kuzating. Jism vertikal yuqoriga qarab harakatlanayotganda, og'irlik jismga manfiy ish bajaradi. Jism yuqoriga harakatlanayotganda, uning balandligi oshadi. Shuning uchun, jismning tortishish potensial energiyasi ham oshadi. Bundan xulosa qilish mumkinki, og'irlik bilan bajarilgan manfiy ish jismning tortishish potensial energiyasining (PE) oshishiga teng.

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Konservativ kuch va konservativ bo'lmagan kuch

1. Konservativ kuch

1.1 Og'irligi (w)

Dastlabki holatiga qarab pastga tushishdan oldin maksimal balandlikka yetguncha vertikal yuqoriga qarab harakatlanayotgan jismni kuzating. Vertikal yuqoriga h ga harakatlanayotganda, og'irlik siljishdan teskari yo'nalishda bo'ladi. Shunday qilib, og'irlik jism ustida manfiy ish bajaradi. 

W = wh (cos 180)^o) = – wh = – mgh

Maksimal balandlikka yetgandan so'ng, jism boshlang'ich holatiga qarab h ga pastga siljiydi. Pastga harakatlanayotganda, og'irlik siljish bilan bir yo'nalishda bo'ladi. U siljish bilan bir yo'nalishda bo'lgani uchun, og'irlik musbat ish bajaradi.

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