Answer:

It will float.
Explanation:
Hello.
In this case, given the width, length and height, we can compute the volume as follows:

Moreover, since the density is computed via the division of the mass by the volume:

We obtain:

In such a way, since the solid has a lower density than the water, we infer it will float.
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No. A mirror works because of reflection.
The atomic number tells you the number of protons in an atom. This value never changes because the number of protons in the nucleus always remains constant. The mass number tells you the number of protons and neutrons (or nucleons) together: protons + neutrons = mass number. Since the number of neutrons in the nucleus varies, you can have different amounts of neutrons in the same type of atom. These varied types are called isotopes.
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