题干

李老师的家离学校大约10km,为了便于上下班,他购买了一部轻便摩托车来代步,使用的燃料为93#汽油。根据表提供的数据,请回答:
(1)如果李老师上班时骑车的平均速度为36km/h,试根据表中所提供的有关信息,为李老师计算一下,他骑车从家到学校至少需花多少油费?

轻便摩托车93#汽油
燃料汽油密度0.7×103kg/m3
油箱容量7L热值4.5×107J/kg
功率6kW价格4.90元/L

(2)小洪同学学过物理以后,给李老师建议:在上述条件不变的情况下,采用加快车速缩短时间的办法,就一定可以省油费。请你根据自己掌握的知识,分析说明这种方法是否可行。

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答案(点此获取答案解析)

解:(1)因为李老师的骑车速度为v=36km/h=10m/s
李老师上学校所用的时间为

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    We all wish we had just a bit more time. Just think what you could do with an extra hour or two each day: you could finally stick to an exercise routine, or spring-clean the house, or write your novel, or learn the guitar and so on. ____ But I can help you find more hours in your day for the things that really matter.

1). Get Out of Bed Earlier

If you normally get up at 7: 30 a. m. , try getting up at 7: 00 a. m. That half-hour might not sound like much, but it could be time that you use to exercise, to read that book you've been meaning to finish. ____

2). Do the Important Tasks First

    Once you get to work, get the important ones done first (not the easy ones, or even the urgent ones). You can afford to spend at least an hour working on big, important tasks rather than on all those little urgent ones. ____The urgent tasks will still get done, and you won't miss the important ones.

3). Reduce Interruptions

    If colleagues have a habit of hanging around your desk to chat, or if the phone is constantly ringing, you might find that it takes you half the day to finish a simple task like writing a letter. Constant interruptions don't just eat up time, they also break your concentration.

    When you've got a big task to focus on, let your calls go to voicemail. ____Wearing headphones makes it less likely that people will try to strike up a conversation.

4). ____

    A few minutes chatting, browsing the web, and so on, can easily turn into hours of wasted time over the course of a day. When you're working, work. If your concentration is slipping, take a proper break: go and get a glass of water, or stretch your legs a bit. And if you're facing a difficult task, try breaking it into small steps or stages so that it's easier to deal with.

A. Or simply to get your day off to a calm and organized start.

B. I can't magically make all your days 25 hours long.

C. Would you want me to make your day longer?

D. Take Breaks When Necessary

E. If you have an office door, close it.

F. If you work like this, you'll usually save time.

G. Stay Focused on Your Work