题干

如图所示,直角形支架,垂直固定放置,竖直杆AC光滑,水平杆OB粗糙。另有质量相等的小球PQ固定在轻杆两端并分别套在AOBO杆上。当轻杆与水平方向的夹角为θ时,处于静止状态,若θ减小些,但PQ仍静止,则下列说法错误的是(  )

A:竖直杆受到P的压力增大

B:水平杆受到的压力增大

C:小球P受到轻杆的支持力增大

D:小球Q受到的摩擦力增大dyszplg

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B

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    Why do many people play sports? You might say “to get exercise'' and you'd be right. To have fun? That's true, too. But there's more.____According to the Women's Sports Foundation, girls who play sports get a lot more than just fit.

    Girls who play sports do better in school. ____But research shows that girls who play sports do better in school than those who don't. Exercise improves learning, memory, and concentration, which can give active girls an advantage in the classroom.

    Girls who play sports learn teamwork and goal-setting skills. Sports teaches valuable life skills. When you working with coaches, trainers, and teammates to win games and achieve goals, you're learning how to be successful. ____

    Sports are good for a girl's health. In addition to being fit and maintaining a healthy weight, girls who play sports are also less likely to smoke. And later in life, girls who exercise are less likely to get breast cancer.

    ____ Girls who play sports feel better about themselves. Why? It builds confidence when you know you can practice, improve, and achieve your goals. Sports are also a feel-good activity because they help girls get in shape, maintain a healthy weight, and make new friends.

    Exercise cuts the pressure. Playing sports can lessen stress and help you feel a little happier. How? ____ Friends are another mood-lifter. And being on a team creates tight bonds between friends. It's good to know your teammates will support you—both on and off the field!

A. Please take action to play games.

B. Playing sports boosts self-confidence.

C. Playing sports is good for your grades.

D. In fact, there are at least 5 more reasons.

E. Those skills will serve you well at work and in family life.

F. You might think that athletics will take up all your study time.

G. The brain chemicals released during exercise improve a person's mood.