如图为某小球从斜面某点无初速度释放、向下做匀加速直线运动的频闪照片，已知频闪相机从小球下滑至A点开始拍摄，此后每隔0.1s曝光一次，测得图中AB=12cm，BC=20cm。求：
小题1:小球在图中B点的速度大小；
小题2:小球运动的加速度大小及A点离释放点的距离。
小题1:1.6m/s
小题2:4cm
（1）设曝光时间为T，
∵小球做初速度为0的匀加速直线运动，
∴
①
（2）据
得：
,
；②
∵
，
据
得：
③
④
| 完形填空。 | |||
| My good friend, Bruce, 1 from England. He is twelve 2 old. 3 father is a teacher. 4 is in China now. His mother is a 5 , too. His mother and his sister 6 come to China. His sister is ten years old. She is a 7 , too. He has some 8 here. They often help him 9 his Chinese. He can speak a little 10 now. | |||
|