问题 选择题

下列关于加速度的说法中,不正确的是(  )

A.加速度不为零时,其速度一定发生改变

B.加速度为零时,物体一定处于静止状态

C.物体的速度变化越快,加速度越大

D.物体的加速度减小,速度可能增大

答案

A、加速度不为零时,物体速度一定发生改变.故A正确.

    B、加速度为零时,物体处于静止状态或匀速直线运动状态.故B错误.

    C、加速度表示物体速度变化的快慢,物体的速度变化越快,加速度越大.故C正确.

    D、物体的加速度减小,当速度与加速度方向相同时,速度增大.故D正确.

本题选错误的,故选B

多项选择题
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阅读理解

     Ask savvy investors(投资者) how they learned their first lessons about money, and they'll probably tell you lessons their parents taught them.

     The money values we learn as children stay with us the rest of our lives. If you are a parent, teaching

your children the value of saving and investing will benefit them the rest of their lives. Here's what you can

do:

     Help your child begin to save. Open savings accounts for your children, and teach them how the bank

adds interest to their savings that makes their money grow. Encourage your children to save a little from

every bit of money they receive, such as allowances, birthday gifts, etc. You may even want to set up a

matching program, contributing fifty cents for each dollar your child saves.

     Teach your child about stocks(股票).  A child in elementary school can start learning  about  how

businesses work. Once your child understands the basics, ask him or her to think about some of  the

businesses that might be good stock investments. Then use Morningstar Mutual Fund Guide(available

at your library) to find a quality mutual fund that holds some of these companies, or a mutual fund that

caters to children such  as  the Stein  Roe  Young  Investor Fund. Many funds  accept regular monthly

investments as low as $50 a month, so these funds can be a good way to teach children about the stock

market while saving for their college education.

     Encourage early IRA(个人退休金账户)saving. The new Roth IRA is a great way for children who

are working in summers or after school to begin saving for their future. Imagine how much money you'd

have today if you had saved $3,000 a year since you were a teenager!

     Let your kids handle their own money. We all learn by doing, so letting your kids manage a segment

of  their budget(预算)will let them earn valuable financial lessons.They may make mistakes, but they will

be small mistakes that may help them avoid larger mistakes as adults.

1.Which would be the best title for this passage?

A.Why to Teach Your Children to Save

B.How to Teach Your Children to Save

C.Tips for Saving for Children

D.Start Good Saving Habits Early

2.A matching program means ________.

A.that you should set a good example to your children

B.that you should provide enough money for children so that they can save some

C.that you encourage your children to compete with each other in saving

D.that you encourage your children by giving some extra money for them to save

3.According to the author, you should teach your children about investment when he/she is ________.

A.in the kindergarten  

B.in primary school

C.in middle school  

D.in college