Identify the situation that have an unbalanced force check all that a that apply

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

The direction of the current in an alternating current circuit remains constant. is direct. changes repeatedly. changes randomly.