Third Law of Motion

When one object exerts a force upon another object, the second object exerts an equal and opposite force upon the first object


Also known as: for every action there is an equal and opposite reaction; the Third Law of Motion addresses balanced and unbalanced forces. When the forces on an object are unbalanced, motion occurs.

The third law of motion explains the generation of thrust by a jet and rocket engine and the motion of a college racing shell.

University of Minnisotta Crew 2002


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Lesson Inquiry

Review the following information and complete the Lesson Inquiry.

Newton's Third Laws of Motion


Describe how the third law of motion moves the racing shell (rowboat) forward?

Describe inertia.

Recall the results of the rocket experiment. How did the balloons illustrate the 3rd Law of Motion?


  1. Take a piece of 8 1/2 by 11 piece of paper.
  2. Fold the paper in fourths.
  3. Tear one of the quarter piece of paper lengthwise. You will have a strip of paper approximately 2 inches wide and 11 inches long.
  4. Prediction -- Will the paper blow upward or downward?
  5. Hold the paper on your bottom lip in blow out over the top of the paper.

What, if any imbalances, caused the result of the experiment?

Complete and turn in a lab write-up.

Done Early?

Research how rockets work. Write and turn-in a one-page essay on the results of research.