问题 计算题

汽车以36 km/h的速度匀速行驶.

(1)若汽车以0.5 m/s2的加速度加速,则10 s后速度能达到多少?

(2)若汽车刹车以0.5 m/s2的加速度减速,则10 s后速度减为多少?位移为多少?

(3)若汽车刹车以2 m/s2的加速度减速,则10 s后速度为多少?位移为多少?

答案

(1)15m/s  (2)5m/s ;125m   (3) 10s后汽车速度为零;25m

题目分析:(1)初速度

加速度,时间t=10s.

10 s后的速度为

.

(2)汽车刹车所用时间

.

位移为

(3)汽车刹车所用时间,所以10s后汽车已经刹车完毕,则10s后汽车速度为零.  

位移

点评:刹车问题是运动规律在实际中的运用时碰到的具体情况,在解答刹车等减速运动问题时,学生往往不加分析直接套用公式,从而造成错解,要正确解决此类问题,首先判断出物体究竟用多长时间,然后才能根据相应的时间带入合适的公式求解。

阅读理解

第三节:阅读理解(共20小题;每小题2分,满分40分)

阅读下列短文,从每题所给的四个选项(A、B、C和D中,选出最佳选项,并在答题卡上将该项涂黑。 

A woman and a man were involved in a car accident on a snowy cold Monday

morning. Both of their cars became totally damaged. But amazingly neither of them was hurt.  God works in mysterious ways.

After they got out of their cars, the woman said, “So you are a man. That’s interesting.  I’m a woman. Wow, just look at our cars ! There is nothing left, but we’re unhurt. This must be a sign from God that we should meet and be friends and live together in peace for the rest of our days.”

Flattered, the man replied, “Oh yes, I agree with you completely. This must be a sign from God!”

The woman continued, “ and look at this, here is another miracle. My car is completely destroyed but this bottle of wine doesn’t break. Surely God wants us to drink this wine and celebrate our good fortune.” Then she handed the bottle to the man.

The man nodded his head in agreement, opened it and drank half the bottle and then handed it back to the woman. The woman took the bottle and immediately put the cap on, and handed it back to the man.

The man asked, “Aren’t you having some?”

The woman replied, “No, I think I’ll just wait for the police---”

56. What is the result of the accident?

A.The drivers were badly hurt. 

B. The cars were completely destroyed

C. the police arrived and saved the drivers.

D. the drivers became good friends

57. The woman told the man to drink the wine to ________.

A. thank God’s help         B. accept her apology

C. celebrate their survival    D. calm down and get relaxed

58. Which of the following words can best describe the woman?

A. tricky    B. friendly   C. generous      D. Optimistic

单项选择题