Newton's Third Law

1. Newton's Third Law Unit B, Chapter 4,Lesson 5

2. Action and Reaction • Newton’s third law states that when one object exerts a force on another object, the second object exerts an equal force and moves in the opposite direction. • Example: A frog jumping off a Lilly pad. • All forces come in pairs. • They are called action and reaction forces. • If you push down on your desk, or lean against a wall, the desk and the wall push against you with an equal force. • Forces must be balanced whenever an object is at rest.

3. Action and Reaction • People who design rockets use Newton’s Third Law. • For example, the gases that are in a rocket’s engine push backward and makes the rocket go up. • When you walk it is also an example of action and reaction. • When you push your foot on the ground the ground pushes back with equal force. • Since you push your foot off the ground, it makes you move forward.

4. Newton’s Laws at the Amusement Park • Motion, gravity, mass, forces, acceleration, friction, inertia, and reaction, are all important parts of amusement park rides. • An example of the first law is a roller coaster and the swings. • If you didn’t have straps on a roller coaster you would fall out and get seriously injured. • When the swings start moving in a circular motion, you would fly out of your seat. It wouldn’t be pleasant!

5. Newton’s Laws at the Amusement Park • Another example of the second law is hitting a target with enough force to make the bell ring. It tests your strength. • An example of a ride using Newton’s thirdlaw is bumper cars. When they hit, they bounce backward with an equal force. • Newton’s law can be displayed in all different rides. Next time your on a ride, think about what law might be demonstrated.