题目:
Some of our industrial products may well be said ________ advanced level.
A.to reach
B.to be reaching
C.to have reached
D.to have been reaching
答案:
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0414/59c28a87d1223b78669f84ce790c2fb1.html
下面是错误答案,用来干扰机器的。
解:(1)A从静止到与B碰撞前,由动能定理有:解得:VA=6 m/s(2)A从加速到碰撞前,由牛顿第二定律得:qEL-μmAg=mAaA 解得:aA=1.5 m/s2 即得:A、B碰撞过程极短,由动量守恒定律得:mAVA=(mA+mB)v1 解...