问题 填空题

在“探究小车速度随时间变化的规律”的实验中:

(1)给出下列的器材,选出实验中所需的器材并填在横线上(填序号).

①打点计时器   ②天平      ③低压交流电源   ④低压直流电源

⑤细线和纸带   ⑥钩码      ⑦秒表           ⑧轨道小车       ⑨刻度尺

选出的器材是:______.

(2)某同学在实验中,用打点计时器记录了被小车拖动的纸带的运动情况,在纸带上确定出A、B、C、D、E共5个计数点.测得计数点间的距离如图1所示,每两个相邻的计数点之间还有四个点未画出来.

①每两个相邻的计数点的时间间隔为______s.

②试根据纸带上各个计数点间的距离,计算出打下B、C、D三个点时小车的瞬时速度,则vB=______m/s,vC=______m/s,vD=______m/s.(保留3位有效数据)

③在图2所示的坐标系中作出小车的v-t图线,并根据图线求出a=______ m/s2

④将图线延长与纵轴相交,交点的速度是______,此速度的物理意义是______.

答案

(1)在“探究小车速度随时间变化的规律”实验中,所需的实验步骤:

(1)木板平放,并使滑轮伸出桌面,把打点计时器固定,连接好电路,(此处所需的仪器有①③⑧)

(2)穿纸带;挂钩码,(此处所需的仪器有⑤⑥)

(3)先接通电源,然后放开小车,让小车拖着纸带运动,打完一条后立即关闭电源,

(4)换纸带,加钩码,再做二次.

(5)处理纸带,解出某位置的速度和运动过程的加速度.(此处所需的仪器⑨)

由实验步骤可以看出需要的仪器有①③⑤⑥⑧⑨,

(2)①由于相邻计数点间还有四个点未画出,所以相邻的计数点间的时间间隔T=0.1s,

②根据匀变速直线运动中时间中点的速度等于该过程中的平均速度,

得:vB=

XAC
tAC
=0.138m/s

vC=

XBD
tBD
=0.264m/s

vD=

XCE
tCE
=0.390m/s

③作图时注意,尽量使描绘的点落在直线上,若不能落地直线上,尽量让其分布在直线两侧.

利用求得的数值作出小车的v-t图线(以打A点时开始记时),并根据图线求出小车运动的加速度a=

△v
△t
=1.26m/s2

④将图线延长与纵轴相交,交点的纵坐标是零时刻的速度大小是0.020m/s,此速度的物理意义是计时初时的速度.

故答案为:(1)①③⑤⑥⑧⑨(2)①0.1  

②0.138    0.264   0.390   ③1.26

④0.020    计时初时的速度

阅读理解

For 52 years my father got up every morning at 5:30 am, except Sunday, and went to work. He returned home at 5:30 pm, for dinner at 6:00 pm. I never remember my father having a night out with his children. All he asked from me as a daughter was to hold his hammer while he repaired something, just so we could have some time to talk to each other.

For 22 years, after I left home for college, my father called me every Sunday. Nine years ago, my father, 67 years old, spent three days painting my house. He asked me to hold the paint brush for him and talk to him. But I was too busy and I could not take the time to hold the paint brush, or talk to my father.

Five years ago, my father spent five hours making a swing(秋千)for my daughter. Again, all he asked me to do was to give him a glass of tea, and talk to him. But again, I had some clothes to wash, and the house to clean.

On January 16, 1996, my father telephoned me as usual, this time from my sister’s home in Florida. I had to get to church, and I cut the conversation short.

The call came at 4:40 pm. That day, my father was in hospital in Florida. I got on an airplane immediately, and on the way, I made up my mind that when I arrived, I would make up for the lost time, and have a nice long talk with him.

I arrived in Florida at 1:00 am, but my father had passed away at 9:12 pm. This time it was he who did not have time to talk, or time to wait for me.

小题1:

When the author was young, her father ______.

A.was busy with his work

B.disliked his children

C.often talked to his children

D.never cared about his children小题2:

How old was the author’s father when he made a swing for his granddaughter?

A.45.

B.67.

C.71.

D.76.小题3:

When painting the house, the father asked the author to hold a paint brush because ______.

A.he wanted to make his work easy

B.he was too old to work all by himself

C.he just wanted his daughter to help him

D.he wanted to have a talk with his daughter小题4:

The underlined phrase “passed away” in the last paragraph probably means “______”.

A.arrived

B.lost

C.left

D.died

填空题