A wooden crate is pushed across a concrete floor at 5m/s and released.It slides to a stop after moving a short distance.
问题描述：
A wooden crate is pushed across a concrete floor at 5m/s and released.It slides to a stop after moving a short distance.The same crate is filled until it weighs twice as much as did previously and again slid across the floor at 5m/s and released.The stopping distance for the crate will be?为什么会是the same distance?0.O
答
但是如果用机械能守恒的话不就不对了吗 1/2mv^2 = fs ;f 变大 那么s自然就变小了啊0.o哥们，f变大，m也变大了。而且f=μmg。所以，距离还是一样的。呵呵 ;] 短路了一下。谢谢啊！~