两个相同的小车并排放在光滑水平桌面上，小车前端系上细线，线的另一端跨过定滑轮各挂一个小盘，盘里分别放有不同质量的砝码（图a）．小车所受的水平拉力F的大小可以认为等于砝码（包括砝码盘）所受的重力大小．小车后端也系有细线，用一只夹子夹住两根细线（图b），控制两辆小车同时开始运动和结束运动．

由于两个小车初速度都是零，运功时间又相同，s=at²/2，即s∝a，只要测出两小车位移s之比就等于它们的加速度a之比．

实验结果是：当小车质量相同时，____；当拉力F相等时，____．

实验中用砝码（包括砝码盘）所受的重力G=mg的大小作为小车所受拉力F的大小，这样做会引起实验误差．为了减小这个误差，G与小车所受重力Mg之间需要满足的关系是：____．

读短文并按要求完成相应任务
    Today was the first day of the summer holiday．My friends and I went out together．We went swimming in the swimming pool．We swam for an hour．I did not swim well，but I enjoyed it very much．We had lunch in a fast—food restaurant．I had a sandwich and some orange juice．Alice had a hamburger．Jack had a lot of French fries and some cola．We went shopping in a supermarket．I bought a pink dress．Alice bought a pretty hat．Jack did not buy anything．
    We went home at 3 o'clock in the afternoon．We 、were tired，but we were happy．

如图甲是晓红设计的“测量小灯泡额定功率”的电路图．已知电源U恒为6V，小灯泡额定电压2.5V．

关于温度、热量、内能，以下说法正确的是（  ）

下列各句中，划线的词语运用正确的一项是（  ）