问题
选择题
关于曲线运动的说法中正确的是
A．做曲线运动物体的加速度方向跟它的速度方向不在同一直线上
B．速度变化的运动必定是曲线运动
C．受恒力作用的物体也可能做曲线运动
D．加速度变化的运动必定是曲线运动
答案
AC
速度大小变化可能是直线运动，B错；只要是加速度方向与速度方向共线就是直线运动，D错；
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关于曲线运动的说法中正确的是
A．做曲线运动物体的加速度方向跟它的速度方向不在同一直线上
B．速度变化的运动必定是曲线运动
C．受恒力作用的物体也可能做曲线运动
D．加速度变化的运动必定是曲线运动
AC
速度大小变化可能是直线运动，B错；只要是加速度方向与速度方向共线就是直线运动，D错；
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| It was very late when we came out of the cinema. We knew the last train would leave 1 11:15, so we ran as 2 as we could to the station. It was just after 11: 15 when we 3 the station, but the trains often leave a little 4 and there was a train standing at Platform 1(第一站台), so we got in. We 5 for half an hour, then we got 6 . We found the ticket collector and asked him 7 the train was going to leave. "Tomorrow morning at six o clock," he told us. There were 8 taxis outside the station. 9 we walked home. It 10 us nearly two hours. The next morning we felt very tired. | ||||
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