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如图所示,相距为L的两条足够长的光滑平行金属导轨与水平面的夹角为θ,上端接有定值电阻R,匀强磁场垂直于导轨平面,磁感应强度为B.将长为L、质量为m的导体棒由静止释放,当导体棒下滑距离L时达最大速度v(v为未知量),导体棒始终与导轨垂直且接触良好,导体棒的电阻为2R,不计导轨的电阻,重力加速度为g,求:

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                                                                                                      Ways to save time

    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 spring­clean 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.

    Get Out of Bed Earlier

    If you normally get up at 7:30 am, try getting up at 7:00 am. That half­hour 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.____

    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.

    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.

    ____

    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