题干

如图所示,一半径为R的均匀带正电圆环水平放置,环心为O点,在O正上方h高位置的A点与A′关于O对称.质量为m的带正电的小球从A点静止释放,并穿过带电环.则小球从A点到A′过程中加速度(a)、重力势能(EpG)、机械能(E)、电势能(Ep)随位置变化的图象一定不正确的是(取O点为坐标原点且重力势能为零,向下为正方向,无限远电势为零)(   )

A:

B:

C:

D:

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D

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    Best Way to Save Money

    Although the best way to save money can vary from person to person, depending on age, family size and other characteristics, there are still some easy things that all shoppers can do to keep more money in their bank accounts.

    Avoid impulse (冲动的) purchases.

    When you shop, a best way to save money is to have a plan in mind to help you avoid impulse purchases.  ____ And you only carry the exact amount of cash that you will need for your planned purchase. Some shoppers agree to discuss any purchases over a certain dollar amount with their spouses (配偶) first.

    ____

    Sometimes the best way to save money in the long term is to spend a little more money right now.  ____ A high-quality pair of shoes will last longer than a bargain pair and prevent foot pain. Leaner (瘦的) cuts of meat and organic produce provide health benefits for your family.

    Buy secondhand.

    Check classified ads, thrift stores and garage sales for used clothing, toys, furniture, and much more available at a part of their original cost.____ And there members offer unwanted items for free to anyone willing to pick them up.

    Borrow instead of buy.

    If you're only going to use something once, try to borrow it instead of spending your money on it. Borrow a tool from your neighbor.____ Check out the resources at your local library. You'll also be reducing disorder in your home.

A. Make things by yourself .

B. Exchange books with a friend.

C. Know when to pay for quality.

D. Refuse to buy things you can't use.

E. For instance, you might leave your credit cards at home.

F. A good piece of furniture can stay in the family for decades.

G. For the most secondhand savings, check out groups like Freecycle.