8 5 - § . M oddiy nuqta va mexanik sistem a harakat miqdorining
momenti
M e x a n ik a m a s a la la rin i y e c h is h d a
h a ra k a t m iq d o ri tu s h u n c h a s i
b ila n b ir
q a to rd a h a ra k a t m iq d o ri m o m e n ti yoki
k in e tik m o m e n t tu s h u n c h a s id a n h a m
fo y d a la n ila d i.
F k uch t a ’s irid a g i
M
m o d d iy n u q ta
V tezlik
bilan h a ra k a tla -
nayotgan b o ‘lsin (162-rasm ).
M n u q tan in g b iro r О m arkazga n is
b atan kinetik m om enti deb m azkur nuq ta
ra d iu s -v e k to ri h a m d a h a ra k a t m iq d o ri
vektorining v ek to r k o ‘paytm asiga ay tila
di va quyidagicha yoziladi:
ко = щ ( т У ) = r x m V .
(85.1)
M oddiy n u q ta kinetik m o m enti vek
to rin in g y o ‘nalish i
r va V y o tg an t e
kislikka p erp en d ik u lar b o ‘ladi.
(85.1)
ni D ekart koordinata o ‘qlariga
proyeksiyalasak, m od d iy n u q ta h a ra k a t
m iq d o rin in g o ‘q q a n isb a ta n m o m e n ti
kelib chiqadi:
Щ (
F )
162-rasm.
163-rasm.
kx = mx ( m V ) =
m( y V z - z V y ) = m ( y z - z y ) ,
ky = my ( m V ) = m (zV x - x Vz ) = m ( z x - x z ) ,
(85.2)
kz = mz ( m V ) =
m{ x Vy - y Vx ) = m( x y - yx) .
K in e tik m o m e n tn in g SI ga k o ‘ra
oM chov birligi kg m
2 / s yoki
N m s ga teng.
M exanik sistem aning b iro r m arkazga nisbatan k in etik m o m e n ti
shu sistem ani tashkil qiluvchi m oddiy nuqtalarning
m azkur m arkazga
nisbatan kinetik m omentlarining geom etrik yig‘indisiga teng (163-rasm).
