题干

如图所示,物体P以一定的初速度沿光滑水平面向右运动,与一个右端固定的轻质弹簧相撞,并被弹簧反向弹回。若弹簧在被压缩过程中始终遵守胡克定律,那么在P与弹簧发生相互作用的整个过程中(      )

A:P做匀变速直线运动

B:P的加速度大小不变,但方向改变一次

C:P的加速度大小不断改变,当加速度数值最大时,速度最小

D:有一段过程,P的加速度逐渐增大,速度也逐渐增大

上一题 下一题 0.0难度 选择题 更新时间:2017-03-02 08:02:50

答案(点此获取答案解析)

C

同类题1

任务型阅读

    Do you have a spare room in your house? What about your driveway for your car?

    Both of these can help you make money. Many people who have financial difficulties are taking advantage of what's been called the 'sharing economy'.

    Perhaps the best-known example of a company in this field is Airbnb.____It says it operates in 34,000 cities and it has 800,000 listings of rooms and apartments. They seem to have cornered the market!

    ____Just Park's founder, Anthony Eskinazi, says: "When I had the original idea, I spotted a driveway close to a sports stadium. It would have been so convenient if I could have just parked in that driveway rather than in a commercial car park." And he has a big clientele(客户): Around 200,000 people have advertised their spaces on the site, and he says around half a million drivers use it.  ____They let drivers share their cars with other passengers.

    ____A church near Kings Cross in central London has apparently made over 200,000 pounds by renting out space in its yard to travelers! But the sharing economy has its competitors. People who run things like traditional hotels, commercial car parks and taxi services are afraid of ending up losing money.____Because this is a new business world, those rules are not there yet. How will renting out your driveway affect your neighbor?

A. Any driver knows how valuable a place to park is.

B. A British company is doing something with parking spaces.

C. There are other sites doing very similar things, like Uber and Lyft.

D. It offers travelers a global network of accommodations offered by locals

E. Another problem is that regulations for these new businesses are unclear.

F. The American web business allows you to rent out your spare room to holidaymakers.

G. Now that the sharing economy is gaining the support of the financial community, corporations start paying attention.