Pixar’s 2004 animated film The Incredibles is a heart-warming and a family friendly movie filled with action, drama, humor, and love. From a physicist’s eyes, it is also filled with physics, both good and bad.
Unlike other styles of animation, Pixar tends to create physically-realistic motion. However, it is important to realize that even though this movie takes place in the real world, some physics laws are altered to adapt to the super powers of the main characters. If many of the stunts were to be performed by a regular person, several physics laws would be broken, but considering they are applied by superheroes, let these fictional physics slide and focus only on the proper application of physics.
One such example is at 8:53 (on my copy) where Mr. Incredible saves a subway filled with passengers. He notices that the track is disconnected and realizes that the approaching subway will fall and smash into the ground if proper action is not taken quickly.
To prevent this, he applies Newton’s 3rd Law (FA = −FB). 3rd law of motion states that for every action force, there is an equal force in the opposite direction. In this scene, Mr. Incredible uses the track and his arms to exert force on the train, while the train simultaneously exerts an opposing force. This results in him stopping the train from going over the edge.
However, the train does not come to a direct halt, but it slows down, pushing Mr. Incredible back as he holds on and pushes his feet into the ground. This is an example of two forces acting upon each other and coming to a balance. Newton’s 1st Law also plays an important role in this scene, which states that an object at rest will remain at rest until an external force is applied to it and that an object moving at a constant velocity will continue moving at a constant velocity unless acted upon by unbalanced force.
For example, the subway and its passengers were moving at a high speed, but when Mr. Incredible applied a counter acting force on the train, the train threw the resting passengers with great force. Mr. Incredible’s ability to apply enough force to bring a running subway to grinding halt maybe fictional physics that makes him a superhero, but Pixar really thought about real world physics of bringing a speeding train to a stop.