为了测定某轿车在平直路上启动阶段的加速度(轿车启动时的运动可近似看成是匀加速直线运动),某人拍摄一张在同一底片上多次曝光的照片,如图所示,如果拍摄时每隔2 s曝光一次,轿车车身总长为4.5 m,那么这辆轿车的加速度为( )
A:1 m/s2
B:2.25 m/s2
C:3 m/s2
D:4.25 m/s2
⑴When is Jack going to watch the film?____ A. My aunt.
⑵What are you going to do this evening?____ B. Tomorrow evening.
⑶Where is Mike going?____ C. I'm going to play the piano.
⑷We are going to have a party.____ D. He's going to the playground.
⑸Who is going to Beijing next week?____ E. Have a good time.
已知:如图,AC和BD相交于点O,OA=OC,OB=OD.
(1)求证:AB∥CD.
(2)取线段OD的中点M,取线段OC的中点N,求MNAB的值.