问题
多项选择题
甲、乙两物体质量之比为m甲：m乙=5：1，甲从H高处自由下落，乙从2H高处同时自由下落，不计空气阻力，以下说法正确的是（）
A.在下落过程中，同一时刻甲的速度比乙的速度大
B.在下落过程中，同一时刻二者速度相等
C.甲、乙在空气中运动的时间之比为1：2
D.甲落地时，乙距地面的高度为H
答案
参考答案：B, D
搜题请搜索小程序“爱下问搜题”
甲、乙两物体质量之比为m甲：m乙=5：1，甲从H高处自由下落，乙从2H高处同时自由下落，不计空气阻力，以下说法正确的是（）
A.在下落过程中，同一时刻甲的速度比乙的速度大
B.在下落过程中，同一时刻二者速度相等
C.甲、乙在空气中运动的时间之比为1：2
D.甲落地时，乙距地面的高度为H
参考答案：B, D
Travelling is a very good activity. When you get tired of your work or study, and when you are not busy, you can go to a beautiful place to enjoy the beauty of nature or other cities. You can take in fresh air, meet different people and make friends with them. It is good for your health to do so. But sometimes, travelling is not an enjoyable thing. For example, the weather can be changeable too often. You may catch a cold or be ill while travelling. The worst thing is some bad persons may steal your money. All these may happen to a tourist. When you go on a trip, you must get everything ready. Firstly, you must have clear information about the weather. Secondly, ask a friend to go with you so that you can help each other. Thirdly, you must be careful everywhere and try not to cause accidents. If you do this, you will surely enjoy our travel.
|