题目

一物体自距地面高H处自由落下，当速度达到着地速度一半时，它下落的高度是（ ）A.H/2          B.3H/4           C.2H/3           D.H/4 答案：D解析：设速度达到着地速度的一半时，它下落的高度为h，则vt2=2gH两式相比可得：h=H/4.The children vary considerably in the rate at which they learn these lessons. _____, we make the teaching plans different accordingly.A. Because of this reason                             B. It is becauseC. As a result of                                          D. For this reason