找出电子平的读数 关于冲量的
A length of rope L of total mass M is suspended at rest just above a digital balance.As the rope is released,find the reading of the pan balance as the rope falls onto the balance as a function of time.
一条绳子　长度为L 质量为M　初始状态是静止　悬挂在电子称平　之上　最低点刚好在称平上.　当绳子　被释放时,　找出电子称平的读数与时间的关系