题干

与23.5ºS相对称的纬线是(   )

A:热带和南温带的界线

B:热带和北温带的界线

C:南温带和南寒带的界线

D:北温带和北寒带的界线

上一题 下一题 0.0难度 选择题 更新时间:2020-02-06 02:25:11

答案(点此获取答案解析)

B

同类题2

阅读短文,回答问题:

汽车在高速行驶过程中一旦发生碰撞,车身停止,而乘员则会继续向前与车身撞击,甚至能把挡风玻璃撞碎而飞出车外.在发生交通事故时,安全带能对人体起到缓冲的作用,防止出现二次伤害.在发生严重撞击时,方向盘等处的车载气囊会自动充气弹出,在人体接触到安全气囊时,安全气囊通过气囊表面的气孔开始排气,从而起到缓冲作用,减轻身体所受冲击力,大大减小伤害.

(1)汽车“发动机”通常都是以汽油或柴油为燃料的,汽油、柴油都属于____ (可再生/不可再生)能源;汽车“发动机”一般需要用水来作冷却剂,这是利用了水的____ 的属性.

(2)一辆汽车沿一平直公路匀速行驶30km,消耗了2kg汽油,该汽车与路面间的摩擦力为690N,则此过程中汽油完全燃烧放出的热量为____ J,该汽车“发动机”的效率为____ .(汽油的热值为4.6×107J/kg)

(3)汽油机是汽车的“心脏”,汽油机的____ 冲程将内能转化为机械能.

(4)对于短文中提到的“缓冲”,小华同学提出了自己的猜想:安全带和安全气囊增加人与碰撞物间的接触时间,从而大大减小撞击力.物理兴趣小组的同学共同设计了如下实验方案:在两个相同的玻璃槽中堆放不同厚度的面粉,用同一只鸡蛋从相同的高度先落在面粉厚度大的槽中,留下较深的坑,鸡蛋完好无损;后落在面粉厚度较小槽中,鸡蛋破裂.实验中通过比较____ 来比较撞击时间的长短,根据实验可以验证小华同学的猜想是____ (正确/错误)的.请列举上述“缓冲”的物理知识在生活中应用的一个实例:____ 

同类题5

任务型阅读

Why I Love Cycling

    One of the first things I did when I moved to a new city was hire a bike. Why?____ You travel much faster than on foot and you notice so much more of your surroundings than when in a bus or a car. It's more appealing to wander down small streets if they seem interesting, as you can quickly get back to the main road.

    Besides, I soon discovered plenty more benefits to cycling.

    A bike means that fewer places, especially in a small city like the one where I live now, feel far away. For example, cycling to work takes me half the time that it would to walk.____

    Of course, there are obvious health benefits of cycling—a bit of extra movement as part of your daily routine can help you keep fit and healthy. Cycling on my way to work also makes me feel more energetic in the mornings.

    ____ While cars pollute the environment, bikes are carbon-neutral. Furthermore, thanks to being petrol-free, bikes are cheaper to run, buy and fix than cars. Even if you don 'town a car, a bike can pay for itself when compared to the price of bus tickets.

    ____ Always wear a helmet, pay attention to other traffic and don't forget your lights at night. Make sure you know the road rules, especially in a new place. Some cities are more cycle-friendly than others.____ Luckily, where I live now is pretty easy to ride a bike around, thanks to having lots of cycle lanes and not too many hills!

A. However, be careful when cycling.

B. I have to learn to ride safely on the right of the road.

C. Importantly, cycling also helps to reduce your carbon footprint.

D. And sometimes city roads are difficult or unpleasant for cyclists.

E. Riding a bike also means you're not restricted by bus timetables.

F. Seeing a city by bike is ideal for settling in and learning your way around.

G. Cycling to work excellently fits for someone who wants to save their pocket money.