Hydrogen gas is harmless to your feet so since you don’t need protection against it that seems the best answer.
Before you start working on any motion problem, YOU decide which direction you're going to call 'positive'. Everybody almost always calls UP positive, and the acceleration of gravity points down, so it winds up negative. But you could just as well call DOWN the positive direction. Then, the cannonball is fired with a negative vertical speed, and the acceleration of gravity eventually robs all of its negative speed, and makes it start falling in the positive direction. The whole thing is your choice.
1. The mass number is protons + neutrons = mass number. In this case, we have protons + neutron = 164.The atomic number is simply the number of protons so we have 43 + neutrons = 164. Subtracting 43 from both sides we get neutrons = 121.
2. = 4
3. The number of protons in the nucleus does not equal the number of neutrons.
A=mass number:
Z=atomic number (= number of protons)
N=number of neutrons:
A=Z+N
If the number of protons in the nucleus is equal the number of neutrons , we would have an even mass number; because Z=N=x; then A=x+x=2x (this is always an even number) but 23 is an odd number, therefore the number of protons in the nucleus does not equal the number of neutrons.
<span>heat capacity→ water has a high heat capacity, and salt water has an even higher one, so the temperatures of the oceans remain within a small range because As the heat rises you get more evaporation which actually cools the ocean down (Specific Heat of Water; Heat needed to break down hydrogen bonds)</span>