均質(zhì)細(xì)直桿AB長(zhǎng)為l,質(zhì)量為m,以勻角速度ω繞O軸轉(zhuǎn)動(dòng),如圖所示,則AB桿的動(dòng)能為:()
A.(1/12)ml2ω2 B.(7/24)ml2ω2 C.(7/48)ml2ω2 D.(7/96)ml2ω2
桿OA與均質(zhì)圓輪的質(zhì)心用光滑鉸鏈A連接,如圖所示,初始時(shí)它們靜止于鉛垂面內(nèi),現(xiàn)將其釋放,則圓輪A所做的運(yùn)動(dòng)為:()
A.平面運(yùn)動(dòng) B.繞軸的定軸轉(zhuǎn)動(dòng) C.平移 D.無(wú)法判斷
均質(zhì)直角曲桿OAB的單位長(zhǎng)度質(zhì)量為ρ,OA=AB=2l,圖示瞬時(shí)以角速度ω、角加速度a繞軸O轉(zhuǎn)動(dòng),該瞬時(shí)此曲桿對(duì)O軸的動(dòng)量矩的大小為:()
A.(40/3)ρl3ω B.(10/3)ρl3a C.(10/3)ρl3ω D.(40/3)ρl3a