— Would you please bring me to eat? — Sorry, there is in the fridge.A. anything; something B. anything; nothingC. something; anything D. something; nothing 答案:D用水平拉力F拉静止在水平桌面上的物块,使之产生加速度a,实验时,多次改变拉力F,并测出相应的加速度,绘出a—F图象如图所示,则物块质量为 kg,物块与桌面间的动摩擦因数为 (g取10m/s2)