问题 问答题

为了测定小木块和长木板之间的动摩擦因数,某同学用垫块将长木板一端垫高使其形成斜面,让小木块从其顶端由静止滑下,再配合其他一些器材,测出了小木块和长木板之间的动摩擦因数.

(1)为完成本实验,在下列可供选择的器材中,该同学选用的器材有______.

(A) 秒表(B) 天平   (C) 刻度尺   (D) 温度计

(2)所需测量的物理量有______;动摩擦因数的计算公式为______.

(3)如果利用DIS实验装置在此倾斜的长木板上完成本实验,写出需要的传感器名称和需测量的物理量:______.

答案

(1)根据实验设计,需要用刻度尺来测出斜面的长度、下滑的高度与底部宽度,同时利用秒表来测量出顶端到底端下滑的时间;

故选:AC

(2)根据牛顿第二定律,则有:mgsinθ-μmgcosθ=ma,则需要测量斜面的长度L与高度h及底部的宽度d,并测出从顶端到底端的下滑的时间,

通过L=

1
2
at2,可知a=
2L
t2
,而sinθ=
h
L
cosθ=
d
L
,因此解得:μ=
h
d
-
2L2
gt2d

(3)若换成DIS实验装置,则可测出滑块下滑到底端的瞬时速度,因此斜面的长度不必要测量,通过光电门传感器来根据v=

s
t
,算出瞬时速度,(s是光电门的宽度,t是通过光电门的时间),根据牛顿第二定律,则有:mgsinθ-μmgcosθ=ma,解得:μ=
h
d
-
vt2
2gd
,因此需要的传感器名称和需测量的物理量是光电门传感器,测出物体到达底端时的速度vt

故答案为:(1)AC(2)斜面长L、底部宽d、高h、物体从顶端滑到底端时间t;μ=

h
d
-
2L2
gt2d

(3)光电门传感器,测出物体到达底端时的速度vt

阅读理解

Europeans are being dug out from heavy snow after a week of very cold weather. The snowstorm is the harshest to hit Europe. Airports were shut down. And schools have been closed for a week.

Until Wednesday, at least 400 people across Europe had died because of the cold temperature. Several countries have said a state of emergency. In Ukraine, temperatures dropped as low as -33℉.

Although the situation is bad, at least one country is hoping the weather will last a little longer. In the Netherlands, the government is preparing for the country’s “11 Cities Tour”. The 125-mile ice-skating marathon will be held along a network which joins 11 towns and cities together in Friesland Province.

The ice along the way must be inches thick for the event. Up to 2 million people are thought to cheer on the race’s 16,000 competitors.

On Wednesday, Dutch soldiers joined in the preparations. They cleaned snow along the way. This will be the 16th time that the event has taken place since the first race in 1909. Dutch General Hans said his soldiers were happy to lend a hand. “We want to do our bit for this national party.” he said.

小题1:What is “11 Cities Tour”?

A.It’s a 125-mile ice skating marathon.

B.It’s a 11-mile ice skating marathon.

C.It’s a 16000-mile ice skating marathon.

D.It’s a 33-mile ice skating marathon.小题2:Which of the following statements is TRUE according to the passage?

A.Thousands of people across Europe died because of the weather.

B.The ice should be less than 6 inches thick for the event.

C.No country is glad to see the cold weather.

D.The first “11 Cities Tour” began in 1909.小题3:Who helped clean snow along the way?

A.French soldiers

B.Dutch soldiers

C.Ukrainian soldiers

D.American soldiers小题4:The underlined word “harshest” means _______ in the passage.

A.safest

B.most enjoyable

C.most serious

D.happiest小题5:The passage is mainly about______.

A.the hard situation Europe faces

B.the European cold weather

C.preparations for a national party

D.the coldest season in Europe

选择题