根据图示回答问题。

1. What's Tom doing?

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2. What's the girl doing?

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3. What's Jim's father doing?

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4. What are they doing?

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5. What's Kevin doing?

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将一个质量为110g的不规则实心物体轻放入盛满纯水的杯中，物体沉入底部，排出1N的水，若向杯中加入盐并搅拌，直到物体悬浮为止．求：

（1）物体在纯水中的浮力；

（2）物体的体积；

（3）物体悬浮时盐水的密度．