Newton's Third Law

Mr. Andersen explains Newton's third law, emphasizing action-reaction pairs. He uses scenarios like pushing a wall or a bowling ball to illustrate these concepts. The video introduces free-body diagrams to identify forces and explains how to construct them, highlighting common mistakes. The video concludes with a review of the learning objectives.

What is the main principle of Newton's Third Law?

• An object in motion stays in motion.

• Energy cannot be created or destroyed.

• For every action, there is an equal and opposite reaction.

• Force equals mass times acceleration.

In space, if you push against a wall, what happens?

• You move towards the wall.

• You accelerate away from the wall.

• You remain stationary.

• The wall moves towards you.

Why don't you move as fast as a bowling ball when pushing it in space?

• The ball is heavier.

• You have a greater mass.

• The ball is lighter.

• You are stationary.

What should not be included in a free-body diagram?

• External forces acting on the body.

• The body itself.

• Forces exerted by other bodies.

• Internal forces within the body.

What is the normal force in a free-body diagram?

• The force of gravity.

• The force exerted by the ground.

• The force of friction.

• The force exerted by the body.

When a person pushes against a wall, which force is not included in the free-body diagram?

• Gravity acting on the person.

• The normal force from the ground.

• The force exerted by the person on the wall.

• The force of the wall on the person.

In a free-body diagram, what does the square represent?

• The forces acting on the body.

• The body itself.

• The ground.

• The direction of acceleration.