设有一质点从A点作曲线运动到B点，如图1所示，A点和B点的位置矢量分别是 
，则它们的大小之差
和它们的矢量差的大小
分别是（）
A: 2m，0
B: -1m，1m
C: 0，0
D: 2m，2m
E: 1m，1m
F: 0，2m
，则它们的大小之差和它们的矢量差的大小分别是（）A: 2m，0
B: -1m，1m
C: 0，0
D: 2m，2m
E: 1m，1m
F: 0，2m
举一反三
- 图示曲柄连杆机构，已知曲柄OA长L，重量不计，连杆AB长2L，重P，受矩为M的力偶和水平力Ｆ的作用，在图示位置平衡。若用虚位移原理求解，则必要的虚位移之间的关系为___________，力F的大小为_____________________。<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/be06434307bd424abfc4ebfe02661f7a.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/b8e7b964d1c84aeca7b22ddef4de87a2.png" />;<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/a584946cde17410c945d6611ff2113b5.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/1aaef24e28ee477ab25dae0a400bf23f.png" />;<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/f3b395453e1d48bdadff2e37dfbbb626.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/be37912822f0451bb15639b7fa0589f1.png" />;<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/6d1112b5c1b4446b93578138388ed79f.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/89b7bcef6b51410cb624a654747d56ee.png" />;<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/0e2b78f437914a1eb8327d13185eaedf.png" />
- What are the comedies of Shakespeare? A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/1882addb95d34f3e877db8ec62e82507.png"/> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/4e230d2e03cc46c2b717155e90fdd081.png"/> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/7f4368645eff4e4b9ec89b237843dabd.png"/> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/5ccbfc9718084d318abfbbe254ae048b.png"/>
- 如图，等直径管，考虑损失，A-A断面为过流断面，B-B断面为水平面，试确定1、2、3、4各点的物理量有以下关系（ ）。<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/221f6e4fdefe4fc8a4dccb77b349aa72.jpg" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/ace37017ba8545728a2182f386058ba6.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/70b91bd905944a2b94af05cde3e27218.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/2000acab49234b1b95b2c3ecc59dfd3c.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/3d47348e1e6f46a99ed44f691c648298.png" />
- Which one is Homer’s epic? A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/60a09e42c1cb4c988adcf2fa43a2170c.png"> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/148a547a82cd4f5482de272b09415b7f.png"> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/bc77b52b6ae747fda43ef56a09994b9f.png"> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/9a18e23e6d9a453ea18eaabd88d99376.png">
- What are the “Four Great Tragedies” of Shakespeare? A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/bf2842136acc4afba0ab8f98320c7d00.png"/> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/ac6493ebe0b44370ac61898fa86c032b.png"/> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/b34e70254de6499eb4641abf0415463b.png"/> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201901/5a8ed85351f948a393c0aca57418e72a.png"/>