题干

下列说法符合物理学史的是 (   )

A:哥白尼发现了海王星

B:开普勒测出了引力常量

C:牛顿发现了万有引力定律

D:卡文迪许发现了行星的运动规律

上一题 下一题 0.0难度 选择题 更新时间:2018-01-03 06:24:02

答案(点此获取答案解析)

C

同类题1

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项,选项中有两项为多余项。(说明:E请填涂AB;F填涂CD;G填涂ABC)

    Any car accident is frightening, but an accident in which your vehicle is thrown into the water, with you trapped inside, is absolutely terrifying. ____

    However, most deaths result from panic, without a plan or understanding what is happening to the car in the water. By adopting a brace position (防冲击姿势), acting decisively and getting out fast, you can save yourself from a sinking vehicle.

    Brace yourself for impact. As soon as you’re aware that you’re going off the road and into a body of water, adopt a brace position. The impact could set off the airbag system in your vehicle, so you should place both hands on the steering wheel in the “ten and two” position.

    Undo your seatbelt. ____ Unbuckle the children, starting with the oldest first. Forget the cellphone call. Your car isn’t going to wait for you to make the call.

    ____ Leave the door alone at this stage and concentrate on the window. A car’s electrical system should work for up to three minutes in water, so try the method of opening it electronically first. Many people don’t think about the window as an escape option either because of panic or misinformation about doors and sinking.

    Break the window. If you aren’t able to open the window, or it only opens halfway, you’ll need to break it with an object or your foot. It may feel counter-intuitive (有悖常理的) to let water into the car. ____

    Escape when the car has equalized. If it has reached the dramatic stage where the car cabin has been filled with water and it has become balanced, you must move quickly and effectively to ensure your survival. ____ 

    While there is still air in the car, take slow, deep breaths and focus on what you’re doing.

A. Open the window as soon as you hit the water.

B. Surviving a sinking car is n ot as difficult as you think.

C. It takes 60 to 120 seconds for a car to fill up with water usually.

D. Such accidents are particularly dangerous due to the risk of drowning.

E. In conclusion, if you know what to do in the water, you’ll be safe.

F. This is the first thing to attend to, yet it often gets forgotten in the panic.

G. But the sooner the window is open, the sooner you can escape directly through it.