在“研究平抛物体的运动”实验中
（1）除了木板、小球、斜槽、铅笔、图钉、坐标纸之外，下列器材中还需要的是______．
A．秒表 B．天平 C．重垂线 D．弹簧测力计
（2）某同学只记录了A、B、C三点，各点的坐标如图所示，则物体运动的初速度为______m/s（g=10m/s2）．
（1）除题目提供的实验器材外，实验还需要重锤线，故选C．
（2）由图示可知，xAB=xBC=15cm，做平抛运动的物体在水平方向上做匀速直线运动，
因此物体从A到B的运动时间与从B到C的运动时间相等，设为t，
物体在竖直方向上做自由落体运动，则yBC-yAB=gt2，
运动时间t=
=yBC-yAB t
=0.1s，(0.4-0.15)-0.15 10
则物体的初速度v0=
=xAB t
=1.5m/s；0.15m 0.1s
故答案为：（1）C；（2）1.5．
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| Our school has a weekly "Parents View" program. Around four years ago, I 1 a call from the headmaster to come to the"Parents View" talk the next morning. After the call I became very nervous and anxious. Many 2 thoughts were coming. One of them was to call the headmaster with 3 and tell him that I could not come. 4 , I gathered some courage. I thought, 5 I missed this opportunity, surely the school would never 6 me again to any of their programs. So, I 7 to go and speak. When my turn came and I started speaking, my heartbeat increased and my mouth went 8 . I wasn't even able to read the written speech 9 . I was not 10 of where I was standing and what I was reading. After my speech, I met with the headmaster and 11 what happened to me. He told me that this happened to everyone. Even great 12 faced the same things when they started. He 13 that I come again. I prepared a topic of talk for the next occasion. This time I was somehow comfortable but not very confident. Afterwards, I met with the headmaster again and told him about the 14 I felt I had made. He was 15 enough to invite me again, but this time to give a 16 to the teachers. I prepared and practiced day and night. With the blessing of God, this went very well and was 17 by the headmaster as well as the teachers because they knew where I started from. They encouraged and praised my 18 . After delivering this presentation successfully, I became 19 . I learned that everything is possible if we have 20 to take the first step. | ||||
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