题目

Canada is a very large country.It is bigger than China.China is the third largest country in the world.Canada is the second largest.It has an area of nearly 10 million sq. km. Canada has a very long coastline.To the west is the Pacific Ocean.To the east is the Atlantic Ocean.The Arctic Ocean is in the north.There are very many islands off the Pacific coast and off the Arctic coast.The biggest one in the west is Vancouver Island.In the east there is New Foundland,and in the Arctic Ocean the biggest islands are Baffin Island and Victoria Island.（Greenland is not part of Canada.It is a part of 科技馆里有一个展品，该展品放在暗处，顶部有一个不断均匀向下喷射水滴的装置，在频闪光源的照射下，可以看到水滴好像静止在空中固定的位置不动，如图所示．某同学为计算该装置喷射水滴的时间间隔，用最小刻度为毫米的刻度尺测量了空中几滴水间的距离，由此可计算出该装置喷射水滴的时间间隔为（g取10 m/s2）        s，图中第2点速度为      m/s.