如图所示,位于固定粗糙斜面上的小物块P,受到一沿斜面向上的拉力F,沿斜面匀速上滑

题型:选择题

问题:

如图所示,位于固定粗糙斜面上的小物块P,受到一沿斜面向上的拉力F,沿斜面匀速上滑。现把力F的方向变为竖直向上,若使物块P仍沿斜面保持原来的速度匀速运动,则(    )

A.力F一定要变小

B.力F一定要变大

C.力F的功率将减小

D.力F的功率将增大

考点:
题型:选择题

金鲤汤功效与作用

题型:选择题

This is a story  that happened 15 years ago but it has always stayed with me since then.On the way back from work every evening,more often than not there would be a homeless man standing at the exit of the freeway.He always waved at every car,he was always happy and smiling and sometimes almost dancing.Every day after work when I got there,I would quickly roll down my window and give him the coins.Occasionally the red light would be on for a minute and we would ask each other about our day.His answer would always be the same,“I’m blessed!”.

It amazed me that even in his situation of being homeless he was so positive,and his answer would remind me of how blessed I was.A single mother of four amazing kids,with a place to call home and with a job to provide for my kids.Then one day I was called into my boss’s office and was told that I was being laid off due to the economy.Needless to say that on my was home that day I was very sad and upset.I didn’t remember to look for my spare change and keep it ready like I usually did.I wasn’t feeling the joy as I got off the ramp where the homeless man would be.Yet there he was as alway,as l turned the ramp.He set his eyes on me,while still smiling and waving at others.

While I was waiting for the red light to turn,he strolled over to my car.He had a big smile he looked me straight in the eyes and said “today I will give you a dollar”.He then reached into his pocket and pulled out a dollar bill.I was blown away.I burst into tears.I wanted to jump out of my car and hug him!

You see that day he gave me more than a dollar bill,he taught me a valuable lesson.No matter  what material things are taken  from you,no one can take away your choice to be joyful.

小题1:What is the passage mainly concerned?

A.A dollar bill from a homeless person.

B.A blessing coming from a homeless person.

C.A woman who lost her job due to the economy.

D.A homeless man standing at the exit of the freeway.小题2:From the lst paragraph,we know the homeless man is         .

A.optimistic

B.brave

C.Iazy

D.kind-hearted小题3:After leaving the boss’s office,the author         .

A.felt relaxed to get rid of the tiring job

B.still felt joyful when coming off the ramp

C.took it for granted that she was fit for her job

D.didn’t put some change aside to give to the man小题4:The underlined phrase“blown away”in the 3rd paragraph most probably  means

       .

A.completely defeated

B.wholly blown down

C.really amazed

D.murdered by gunfire小题5:It can be inferred from the passage that         .

A.material things are the most important in life

B.people should be encouraged to beg by smiling

C.the author’s ride home that dog was smooth sailing

D.we should wait others’help when faced with challenges

题型:选择题

在Access 2003中,用数据库向导建立数据库,数据部分不需要用户自己输入。

题型:选择题

电容器电容量测量中,设备要求()。

A.待试电容器为冷备用状态

B.待试电容器为检修状态

C.待试电容器已充分放电并接地

D.设备外壳可靠接地

题型:选择题

下列程序的输出结果是______。
#include<stdio.h>
main()
int x=1, y=1,a=1,b=1;
switch(x)
case 1:
switch (y)
case 0:a++; break;
case 1:b++; break;

case2: a++: b++; break;

printf("a=%d,b=%d\n",a,b);

更多题库