Newton's Third Law of Motion :
Newton's Third Law of Motion Newton's third law of motion states that for every action, there is an equal and opposite reaction. When you lay down in bed, your body exerts a downward force onto the bed. At the same time, the bed exerts an upward force onto your body. The two forces are equal in magnitude and opposite in direction. The force that you exert on the bed is known as the action force, and the force the bed exerts on your body is known as the reaction force . Every time two objects interact, there is a pair of forces. The forces are equal in magnitude and opposite in direction. These forces are known as force pairs .
Equal and Opposite Forces :
Equal and Opposite Forces The animation below shows a ball being dropped in slow motion. When the ball strikes the ground, it exerts a force on the ground. The ground also exerts a force on the ball that is equal in magnitude and opposite in direction. http://www.youtube.com/watch?v=tua7CfMMRrM
Equal and Opposite Forces (cont.) :
Equal and Opposite Forces (cont.) There are several force pairs occurring in the scenario below. Assume there is no friction acting on the balls as they move back and forth. Scenario: A blue ball on the left rolls on a flat surface. A red ball on the right rolls on the same surface. Both balls roll toward each other to the middle and collide. They then roll to their side until they hit the end of the surface. Then they roll back toward each other again until they meet in the middle where they collide again. What are some of the force pairs?
Force Pairs :
Force Pairs The force pairs in this scenario include: 1. When the two balls collide, the red ball exerts a force on the blue ball in a leftward direction. At the same time, the blue ball exerts an equal and opposite force on the red ball in a rightward direction. 2. When the blue ball strikes the end of the box, the blue ball exerts a force on the box in a leftward direction. At the same time, the box exerts an equal and opposite force on the blue ball in a rightward direction. 3. When the red ball strikes the end of the box, the red ball exerts a force on the box in a rightward direction. At the same time, the box exerts an equal and opposite force on the red ball in a leftward direction.
What You Have Learned :
What You Have Learned You learned about Newton's third law of motion. - Newton's third law of motion states that for every action, there is an equal and opposite reaction. - Force pairs are equal in magnitude and opposite in direction.