Newton’s 3rd Law of Motion: Action and Reaction. Book M Section 2.4 Pages: 64-69. Newton realized that forces are not “one-sided.” Whenever one object exerts a force on a second object, the second object exerts a force back on the first object.
You may already be familiar with examples of Newton’s third law of motion.
A squid applies Newton’s third law of motion to move itself through the water.
You have already learned that balanced forces, which are equal and opposite, add up to zero.
To answer this question, you have to consider the object on which the forces are acting.
Newton’s third law, however, refers to forces on two different objects.
The action and reaction forces cannot be added together because they are acting on different objects.
Newton also wrote about something that he called the “quantity of motion.”
Momentum is useful for understanding what happens when an object collides with another object.
However--the word conservation means something different in physical science than in everyday usage.