A:当振子稳定振动时,它的振动周期是0.5
B:当振子稳定振动时,它的振动周期是0.25
C:当摇把转速为240 r/min时,弹簧振子的振幅最大,若减小摇把转速,弹簧振子的振幅一定减小
D:若摇把转速从240 r/min进一步增大,弹簧振子的振幅也增大
选择正确答案
A dog is walking along a road. It is a big dog. It is carrying a piece of meat. The piece of meat is in the dog's mouth. The dog is walking across a bridge now.There is water under the bridge. The water is very deep. The dog is looking into the water. It can see a dog in the water. This dog has a piece of meat in its mouth, too. The big dog is barking at the dog in the water. It wants its piece of meat, too. The big dog's piece of meat is falling into the water.
“神舟”十号飞船于2013年6月11日17时38分发射升空,如图所示,在“神舟”十号靠近轨道沿曲线从M点到N点的飞行过程中,速度逐渐减小.在此过程中“神舟”十号所受合力的方向可能是( )
口号和名词往往是一个时代的见证。热播电视剧《父母爱情》中的“破四旧”“造反有理”“右派”“走资派”等口号和名词应出现在哪一历史时期( )