SAT2巴朗物理 P61最下方说how far the object has fallen when it is 10 meters away from the base,if the horizonal velocity is 10 meters per second.The answer is -4.9.很奇怪为什么这里的4.9要加负号?问题中不是说how far has fallen
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SAT2巴朗物理 P61最下方说how far the object has fallen when it is 10 meters away from the base,if the horizonal velocity is 10 meters per second.The answer is -4.9.很奇怪为什么这里的4.9要加负号?问题中不是说how far has fallen
SAT2巴朗物理 P61最下方
说
how far the object has fallen when it is 10 meters away from the base,if the horizonal velocity is 10 meters per second.The answer is -4.9.
很奇怪为什么这里的4.9要加负号?问题中不是说how far has fallen吗?
既然已经是在问坠落多少那么回答一个负数岂不是说这个物体在上升?（就像温度降低了-3℃其实就是上升了3℃一样）
SAT2巴朗物理 P61最下方说how far the object has fallen when it is 10 meters away from the base,if the horizonal velocity is 10 meters per second.The answer is -4.9.很奇怪为什么这里的4.9要加负号?问题中不是说how far has fallen
这里计算说用上面的trajectory formula,所以最后结果有负号.不要太纠结正负号,书里取向上为正方向,所以下降多少米就加负号了.至于问题里是fall,因为就是下降这样问很准确啊.而且最后它说answer是-4.9,没有说它fall down -4.9 别在意这个了~
哪一版的巴朗？