Question

a person stands on a skateboard and pushes against a wall. predict what will happen and explain why, using newtons third law.
the person will move toward the wall because the wall pulls them.
the person will stay still because the forces cancel out.
the person will move away from the wall because the wall pushes back with equal force.
the person will fall off the skateboard due to gravity.

Explanation:

Newton's Third Law states that for every action, there is an equal and opposite reaction. When the person pushes against the wall (action force), the wall pushes back on the person (reaction force) with equal magnitude. Since the person is on a skateboard (which reduces friction), this reaction force from the wall will cause the person to move. The movement is away from the wall because the reaction force is opposite in direction to the action force (the push against the wall). The other options are incorrect:

• The wall doesn't "pull" (so the first option is wrong).
• Forces don't cancel out here as they act on different objects (the person pushes the wall, wall pushes the person - these are an action - reaction pair, not balanced forces on the same object, so the second option is wrong).
• Gravity acts vertically (downward), and there's no indication it causes a fall off the skateboard in this horizontal - push scenario (so the fourth option is wrong).

Answer:

The person will move away from the wall because the wall pushes back with equal force.