Firstly, the density of any substance is represented by the mass (amount of matter) as divided by the volume(amount of space). According to external websites, the mass of a penny is 2.5 grams.However, the volume of a penny is .35cm to the power of 3 (due to the thickness of the penny being extremely minimal.Thus the amount of density is extremely little). Therefore, the density of a penny is 0.875 g/cm cubed (dimensional analysis).As for an invention that could be used, that is possible with the usage of a series of measurements that can both calculate mass and volume and directly allocate that to attain density
For #1 the answer is dependent relationship . 2. answer is independent relationship . the last question the answer is dependent.
I know they are fishing and there is an alligator in the lake. The alligator might grab the bait and attack the fishers.
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Y is Po-218.
<h3>Explanation </h3>

Here's the symbol of a particle in a nuclear reaction.
.
A stands for mass number. Z stands for atomic number. Both numbers shall conserve in a nuclear reaction.
- The mass number on the left hand side is 222.
- The two mass numbers on the right hand side add up to A + 4.
- 222 = A + 4.
- A = 218
So is the case for the atomic number. Try figure out the atomic number of Y using the same approach.
- The atomic number on the left hand side is 86.
- The two atomic number on the right hand side add up to __ + __.
- 86 = __ + __.
- Z = 84.
What element is Y? The atomic number of Y is 84. Refer to a periodic table. Element 84 corresponds to Po (polonium). Y is Polonium-218. The symbol of Y should be written as
. Hence the equation:
.