【单选题】如图 2所示,质量 m = 10 kg的物体,在水平地面上向左运动,物体与水平地面间的动摩擦因数 μ = 0.2,与此同时,物体受到一个水平向右的推力 F = 20 N的作用,则物体的加速度为(取 g = 10 m/s 2 )
【简答题】完形填空。 Last summer, I was a volunteer (志愿者) at a shelter for the homeless, a place for homeless people to sleep at night. I wasn't working that summer and was taking only two classes in summer school, ...
【简答题】如何实现两个客户端通信?试编程加以说明。
【简答题】水平地面上的一个物体,受到水平向右大小为20N的拉力F,请在图中,用力的示意图把它表示出来.
【单选题】This earthquake _______ several cities in the vicinity, resulting in hundreds of people homeles s.
【单选题】The Wenchuan earthquake in 2008 is believed _____ more than 70,000 people and made thousands homeless, _____ it perhaps the most destroying earthquake in history. [ ]
B.
to have killed; making
C.
having killed; to make
【单选题】一个物体放在水平地面上,下列关于物体和地面受力情况的叙述正确的是( )