问题 选择题

在《验证牛顿第二定律》实验中,下面的说法中正确的是

A.平衡摩擦力时,小桶应用细线通过法滑轮系在小车上,但小桶内不能装砂

B.实验中应始终保持小车和砝码的质量远大于砂和小桶的质量

C.实验中如用纵坐标表示加速度,用横坐标表示小车和车内砝码的总质量,描出相应的点在一条直线上,即可证明加速度与质量成反比

D.平衡摩擦力时,小车后面的纸带必须连好,因为运动过程中纸带也要受到阻力

答案

BD

题目分析:在《验证牛顿第二定律》实验中平衡摩擦力时,小车后面的纸带必须连好,因为运动过程中纸带也要受到阻力,D对;小车前不栓细线,不挂任何物体,A错;为了减小实验误差,实验中应始终保持小车和砝码的质量远大于砂和小桶的质量,B对;若实验中如用纵坐标表示加速度,用横坐标表示小车和车内砝码的总质量的倒数,描出相应的点应在一条直线上,即可证明加速度与质量成反比,C错。

点评:学生明确在《验证牛顿第二定律》实验中平衡摩擦力时,要求要带着纸带平衡,实验中还要求小车和砝码的质量远大于砂和小桶的质量。

阅读理解

TV Shows and Long Bus Trips

Long bus rides are like television shows. They have a beginning, a middle, and an end— with ads thrown in every three or four minutes. The ads are unavoidable. They happen whether you want them or not. Every couple of minutes a billboard appears outside the bus window.“Buy Super Clean Toothpaste.”“Drink Good’n Wet Root Beer.”“Fill up with Pacific Gas.” Only if you sleep, which is equal to turning the television set off, are you spared the unending cry of “You Need It! Buy It Now!”

The beginning of the ride is comfortable and somewhat exciting, even if you’ve traveled that way before. Usually some things have changed—new houses, new buildings, sometimes even a new road. The bus driver has a style of driving and it’s fun to try to figure it out the first hour or so. If the driver is particularly daring, the ride can be as exciting as a suspense(悬念) story. Will the driver pass the truck in time? Will the driver move into the right or the left-hand lane?After a while, of course, the excitement dies down. Sleeping for a while helps pass the middle hours of the ride. Food always makes bus rides more interesting. But you’ve got to be careful of what kind of food you eat. Too much salty food can make you very thirsty between stops.

The end of the ride is somewhat like the beginning. You know it will soon be over and there’s a kind of expectation and excitement in that. The seat, of course, has become harder as the hours have passed. By now you’ve sat with your legs crossed, with your hands in your lap, with your hands on the arm rests—even with your hands crossed behind your head. The end comes just at the right time. There are just no more ways to sit.

小题1:According to the passage, what do the passengers usually see when they are on a long bus trip?

A.Buses on the road.

B.Films on television.

C.Advertisements on billboards.

D.Gas stations.小题2:What is the purpose of this passage?

A.To talk about the similarities between long bus trips and TV shows.

B.To persuade you to take a long bus trip.

C.To display the differences between long bus trips and TV shows.

D.To describe the billboards along the road.小题3:The writer of this passage would probably favor      

A.bus drivers who weren’t caring.

B.driving alone.

C.a television set on the bus.

D.no billboards along the road.小题4:The writer feels long bus rides are like TV shows because     

A.the ads both on TV shows and on the billboards along the road are fun.

B.they both have a beginning, a middle, and an end, with commercials in between.

C.the drivers are always daring on TV shows just as they are on buses.

D.both traveling and watching TV are not exciting.小题5:The writer thinks that the end of the ride is somewhat like the beginning because both are   

A.exciting.

B.comfortable.

C.tiring.

D.boring.

单项选择题