纸币流通情况下,由于货币供应过多而引起货币贬值,物价总水平持续上涨的经济现象称为( )。
A.经济反弹
B.物价上涨
C.通货膨胀
D.财政赤字
参考答案:C
阅读短文,回答下面的问题。
Jenny and Danny are watching TV. Jenny is sitting in a chair and Danny is sitting beside her. Bob and Lynn
are playing cards. Mr. and Mrs. Smith are sitting on the couch. They are reading the newspaper.
1. What are Jenny and Danny doing?
2. What are Bob and Lynn doing?
3. What are Mr. and Mrs. Smith doing?
如图所示,长度为ι的轻绳上端固定在O点,下端系一质量为m的小球(小球的大小可以忽略)。
(1 )在水平拉力F 的作用下,轻绳与竖直方向的夹角为α,小球保持静止,画出此时小球的受力图,并求力F 的大小。
(2 )由图示位置无初速度释放小球,求当小球通过最低点时的速度大小及轻绳对小球的拉力,不计空气阻力。