C. The person's feet push backward on the sidewalk; the sidewalk pushes forward on the person.
This is due to our kick back motion forced on the sidewalk when we walk, and the resistance of us walking on it createsa push forward.
Hope this helps!
Answer:

Explanation:
Given that

As both charges are negative so there exist force of repulsion in direction as shown in figure.

Angle at which force F12 is acting is



Force exerted on charge -2e is equal in magnitude to F12 but is in opposite direction


Products such as antifreeze are composed of organic compounds that are classified as <em>alcohols</em>. (a)
Maybe those other classes of chemicals also lower the freezing temperature of water, just like alcohol does. I don't know. But alcohol is what's used to make anti-freeze. I'm guessing alcohol must be cheaper, less toxic, and less corrosive inside the engines' cooling systems than any of that other stuff is.
The atom in an excited state has more energy and is less stable than the atom in the ground state.
50% of the moon is always illuminated, however during it's quarter phase means that we only see a quarter of what's really lit up. So it LOOKS like the moon is only 25% lit and 75% dark, it's truly 50/50. We only see that 25% since we can see it from one angle.