己知天然气的热值为4.2×107J/m3 ,水的比热容为4.2×103 J/(kg.℃).
—A movie called X Men 2 is on show these days. Would you like to see it with me?
—Sorry. I ______ it already. But it is really exciting.
匀速前进的车厢顶部用细线竖直悬挂一小球,如图所示,小球下方与一光滑斜面接触.关于小球的受力,说法正确的是( )
①月球是一个球体②月球本身不发光③月球绕地球运动 ④月球相对太阳位置的变化
下列诗句中与其蕴涵的物理知识相对应不正确的是( )