當(dāng)質(zhì)點(diǎn)系運(yùn)動(dòng)時(shí),其質(zhì)心C的矢徑由式(2-30)給出為式中mi為質(zhì)點(diǎn)系第i個(gè)質(zhì)點(diǎn)的質(zhì)量,ri為質(zhì)點(diǎn)系第i個(gè)質(zhì)點(diǎn)的矢徑,M為質(zhì)點(diǎn)系的總質(zhì)量。對(duì)上式兩邊分別對(duì)時(shí)間求導(dǎo)數(shù),得或上式中(drC)/(dt)=vC為質(zhì)心的速度,(dri)/(dt)=vi為第i個(gè)質(zhì)點(diǎn)的速度,故有 (共 1221 字) [閱讀本文] >>