题干

如图甲所示,用粗细均匀的导线制成的一只单匝圆形金属圈,现被一根绝缘丝线悬挂在竖直平面内处于静止状态,已知金属圈的质量为m=0.1kg,半径为r=0.1m,导线单位长度的阻值为ρ=0.1Ω/m,.金属圈的上半部分处在一方向垂直圈面向里的有界匀强磁场中,磁感应强度B随时间t的变化关系如图乙所示.金属圈下半部分在磁场外.已知从t=0时刻起,测得经过10s丝线刚好被拉断.重力加速度g取10m/s2.求:

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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.

同类题4

阅读下面材料

材料一:在影响我国的自然灾害中,以洪涝和干旱的发生频率最高、影响范围最广。今年我国江淮流域入汛比常年偏早16天,平均降水量(251毫米)比常年同期(203毫米)偏多23%,特别是暴雨多、强度大,而水利又常年失修、城市排水不畅,致使江淮流域多地内涝、“城市看海”现象多发。但因降水相对分散,尚未形成像98年那样的流域性大洪水,***在视察武汉时说:当前不少城市出现“看海”,这既有降雨集中的因素,也反映出城市建设历史欠账较多。防汛抗洪基础在“防”,关键在“抗”,核心在“人”。

材料二:中华民族5000年的文明史也是同大自然不断斗争的历史。大禹是中国最早治理大洪水的领袖人物,他改堵为疏取得了成功。还有西门豹、李冰、郭守敬等人的治水思想成为中华文化中的瑰宝,至今仍值得借鉴。中华民族还在长久与洪水的斗争中形成了“三过家门而不入”的精神、以98抗洪为代表的“抗洪精神”;同时随着我国科技的发展我们对雨情、水情监测预报、预警更加及时、准确;对灾害发生规律的认识更加科学。***在唐山参加抗震40周年纪念活动时说:我们开展的许多重大抗灾救灾和灾后重建取得的伟大成就启示我们:只要紧紧依靠***的坚强领导、充分发挥我国社会主义制度的优势,我们就能不断把中国特色社会主义伟大事业推向前进。

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