一球从100米高度自由落下，每次落地后反跳回原高度的一半。求它第10次落地时，共经过多少米。第10次落体反弹有多高？-A ball from a height of 100 m free fall, and every time after landing back to the original half of the height of the river. For it 10 th born, of how many meters. 10 times fall how high rebound?