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

 , (1.1)

t
bunda, S - bosib o’tilgan yo’l, t – vaqt.

Definition of velocity

The velocity of an object at any given moment is the slope of the tangent line through the relevant point on its x-t graph.One interpretation of this definition is that the velocity tells us how many meters the object would have traveled in one second, if it had continued moving at the same speed for at least one second. To some people the graphical nature of this definition seems “inaccurate” or “not mathematical.” The equation v=x/t by itself, however, is only valid if the velocity is constant, and so cannot serve as a general definition. ¹[1]
Odatda, fizikada tezlik deganda moddiy nuqtaning traektoriya bo’ylab ko’chish tezligini va har bir momentdagi nuqtaning harakat yo’nalishini xarakterlovchi fizik kattalik tushuniladi. SHu sababli traektoriyaning har bir nuqtasi uchun oniy tezlik tushunchasi kiritilgan. Oniy tezlikni topish uchun x, u koordinata o’qlari tekisligida biror harakatning traektoriyasini quramiz va bu traektoriyaning cheksiz kichik biror dl qismiga mos bo’lgan ds ko’chishni ajratib, unga koordinata boshidan r₁ va r₂ radius-vektorlarni o’tkazamiz. Endi ds ko’chishni shu ko’chish sodir bo’lgan dt vaqt oralig’iga bo’lib, traektoriyaning shu nuqtasi uchun oniy tezlikni topamiz.
S dS
V  lim  . (1.2)
t0 t dt
Bu yerda , V — oniy tezlik, ds — cheksiz kichik ko’chish, dt — vaqt oralig’i. Demak, tezlik moddiy nuqtaning radius- vektoridan vaqt bo’yicha olingan hosilasiga teng ekan. Tezlik V traektoriyaga urinma bo’ylab yo’nalgan bo’ladi. Xalqaro Birliklar Sistemasi da tezlik birligi m/s, SGS sistemada sm/s. YAna tezlik amaliyotda km/soat birlikda ham o’lchanadi.

(1.1) (1.2)
To’g’ri chiziqli tekis harakatda yo’llarni qo’shish quyidagicha (1.3 rasm)

S  S₁  S₂ ... S_n ²
To’g’ri chiziqli harakatda tezliklarni qo’shish quyidagicha (1.4-rasm)


V V₁ V₂ ...V_n
V  V₁ V₂
V²  V²₁ V₂²  2V₁ V₂сos

22. 
     v12 v22
    

To’g’ri chiziqli tekis o’zgaruvchan harakat deb, traektpriyasi to’g’ri chiziqdan iborat bo’lgan va teng vaqtlar oralig’ida har xil masofalar o’tiladigan harakatga aytiladi.
Under conditions of constant acceleration, we can relate velocity and time,
or, as in the example 1, position and time,
² [2]
Moddiy nuqtaning tezligi vaqtning funksiyasidir. Shu sababli tezlikdan vaqt bo’yicha olingan hosila tezlanish ni beradi:
dV d ²S

22. 
      ₂ . (1.3) dt dt
    

Tezlanish ham vektor kattalikdir. Tezlanishning XBS dagi birligi m/s².
2
-25
Endi egri chiziqli harakatda tezlik va tezlanishni ko’ramiz. Egri chiziqli harakatda tezlik vektori ham qiymat bo’yicha, ham yo’nalish bo’yicha o’zgarib turadi. SHu sababli tezlanish harakat yo’nalishi bilan bir xil bo’lmaydi. Tezlanish W vektorini egri c