<span>Answer: A) They are isotopes of nitrogen and they contain the same number of protons and electrons but each contains a different number of neutrons - 7 and 8 respectively.
Isotopes are atoms of a chemical element whose nucleus has the same atomic number, Z, but different atomic mass, A. The atomic number corresponds to the number of protons in the atom, therefore the isotopes of an element contain the same number of protons and electrons (atoms have to be neutral particles). The difference in atomic masses arises from the difference in the number of neutrons in the atomic nucleus.
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Momentum = velocity * mass. Momentum is always conserved. The ball's momentum before the impact is 0.05Vo. After the impact, it is 105Vf. (Vf = final velocity). Because momentum is conserved, we know that:
0.05Vo = 1.05Vf...
Vo = 21Vf...
Vf = Vo / 21.
Density = (mass) / (volume)
= (50.4) / (57.9) = 0.87 gm/cm³
Since the density is less than 1.0, the paraffin floats in water.
Since it's so close to 1.0 on the low side, the paraffin floats
with most of it under the water line.