题目

一物体从离地80m高处下落做自由落体运动．（g取10m/s2）求：                                   （1）物体下落的总时间为多少？                                                                                    （2）物体落地速度？                                                                                                     （3）下Every student in Australia(澳大利亚)must wear their school uniforms when they are at school．There are many kinds of uniforms such as suits，dresses，shorts，skirts，shirts，T-shirts and so on．Class usually begins at 8：00 a．m．in most Australian schools，and sometimes it begins at 10：00 a．m．You needn’t go to class with your schoolbag，you can put it in your own cabinet(书桌)and only take a few books．There are many subjects：English，Maths，Biology，Geography，History，Physics，Chemistry(化学)，Music，Computer，PE，Chinese Drama and so on．In a computer class，each student sits at a table and does their work．They are very quiet．The teacher goes around them to give directions(说明)to them．One class is about two hours．At noon all the students have lunch at school．Their lunch is sandwiches and some fruit．In the afternoon there’s only one class．School ends at 3：30 P．m．Some students can swim or play ball games until 5：30 P．m．Then they must go home．They seldom do homework，even the students in Grade Eleven．This is the school life of the Students in Australia．1.In a computer class，each student is very_________．A．quiet B．noisy C．happy D．sad，2.When is school over in Australia?A．At 5：30 P．m B．At 3：30 P．mC．At 4：00 P．m D．At 5：00 P．m．3.Which sentence is RIGHT?A．The students go to class with their schoolbags．B．One class is about one hour．C．The students always have much homework．D．The students don’t often do homework．