试题与答案

如图所示,AB1、AB2是两个光滑斜面。使一个物体先后从A点由静止开始沿两个斜面

题型:选择题

题目:

如图所示,AB1、AB2是两个光滑斜面。使一个物体先后从A点由静止开始沿两个斜面滑下,分别滑到斜面底端B1和B2处,则比较物体在两个斜面上滑动的情况,下面结论正确的是

A.物体沿AB1斜面下滑的加速度大

B.物体沿AB1斜面滑到底端用的时间短

C.物体沿AB1斜面滑到底端时的速度大

D.物体沿两个斜面到底端时的速度一样大

答案:

ABD

题目分析:物体沿光滑斜面下滑的加速度a=gsinθ,所以物体沿AB1斜面下滑的加速度大,故A对;

设A的高度为h,物体下滑的位移x=h/sinθ,由运动学公式,由静止开始沿两个斜面滑下有时间t=,所以物体沿AB1斜面滑到底端用的时间短,故B对;到达底端的速度v=

=,沿这两个斜面下滑到底端的速度大小相等,故C错,D对。

试题推荐
题型:填空题

mine, nothing , thought, hurt, free, arrived , door, surprise, carefully, mother’s
Lunch Made of Love
In those poor times, many of my classmates couldn’t bring a nice meal to school for lunch. My deskmate’s meal was always cabbages, while 66  (我的)was ham and fried eggs. Sometimes, my deskmate would first pick the hair out of his lunch and then eat it as if   67 (没事)had happened. This continued for a long time.
“His mother is so lousy(邋遢的)that her hair drops in the meal, ”my classmates said. I  68  (想)it was really dirty, but I couldn’t show that because I didn’t want to hurt(伤害)his feelings. Still, I started to think that he was   69 (肮脏), too.
One day after school, he called me and said, “Would you like to come to my house if you are  70 
(有空)? ”
Though I didn’t want to go, I knew it would be impolite to refuse because this was his first invitation. Following my friend, we   71  (到达)at a poor village.
“Mom, I brought my friend home. ”
His old mother opened the   72 (门), “My son’s friend is here. Let me have a look. ”But to my
  73 (惊讶), his mother was blind. She couldn’t see anything.
I felt sad. Now I understood why my deskmate’s lunch had hair in it. His mother got ready for it
  74  (仔细)for him every day, even though she was blind. It was not only a lunch, but also a   75  
(母亲)love.
查看答案
微信公众账号搜索答案