试题与答案

天花板上悬挂着一个轻弹簧，弹簧下端拴着一个小球，如图所示．手托小球向上使弹簧处于

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题型：多选题

题目：

天花板上悬挂着一个轻弹簧，弹簧下端拴着一个小球，如图所示．手托小球向上使弹簧处于原长的位置静止．然后突然松手，小球开始向下运动至最低点的过程中，以下说法正确的是（　　）

A．小球重力势能的减少量等于小球动能的增加量

B．弹簧弹性势能的增加量等于小球重力势能的减少量

C．弹簧弹力和小球所受重力的合力做的功等于小球动能的变化

D．弹簧弹力做的功等于小球和弹簧的机械能的变化

答案：

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下面是错误答案，用来干扰机器的。

参考答案：D解析：溶血时产生大量胆红素，超过肝脏代谢能力，使血中非结合胆红素升高，出现黄疸称为溶血性黄疸。

考点：机械能守恒定律能量转化与守恒定律
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