题型:填空题 在用如图所示的装置做”验证动量守恒定律”实验时,入射球a的质量为m1,被碰球b的质量为m2,小球的半径为r,各小球的落地点如图所示,下列关于这个实验的说法正确的是______ A.入射球与被碰球最好采用大小相同、质量相同的小球B.让入射球与被碰球连续10次相碰,每次都要使入射小球从斜槽上不同的位置滚下C.要验证的表达式是m1.ON=m1.OM+m2.OP.D.要验证的表达式是m1.OP=m1.OM+m2.ON. 查看答案
题型:填空题 用 is / isn't / am / are 填空1. This my teacher .2. I fine.3. Is she Maria ?No, she 4. you Jane ? No, I not. I Maria.5. he Kangkang? No ,he .He Michael.6. What this in English ? 查看答案
题型:填空题 156. As is known to all, hard work will _____ in time.A.pay outB.pay backC.pay upD.pay off 查看答案