Why is there damage done when a crash occurs? How do the colliding objects interact?
Concept: For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction.
Guiding Question: What causes a rocket to take off?
Newton’s Third Law states that “for every action, there is an equal and opposite reaction.” In a collision, energy is transferred from one vehicle to the other. The magnitude of this energy depends on factors such as speed, mass, and protections against collision.
PHENOMENON
Notes and Reading Resources
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LABS
LAB: Newton's 3rd Law
Watch the video to complete the lab. Pause the video when the camera zooms in on the measurements. It may be a bit hard to read, but you should be able to see it and write it down.
In the first part, the student on the left pulls on the spring scale while the student on the right stays completely still. What are the readings?
In the second part, both students are pulling at the same time. What is the reading on both scales now!?
Lab: Pool Ball Collisions.
First, make predictions about how the objects will move when they collide. After you have made your predictions, watch the video to the right and write what you observed. Then answer the follow up questions on your worksheet
LAB: Newton's 3rd Law with balloon
Watch the video to complete the lab.
Why is the balloon moving across the string? How can we use Newton's Third Law to explain this.
Videos
Vocabulary
- Force - a push or pull on an object
- Mass - A measure of how much matter is in an object
- Acceleration - The rate at which velocity changes
- Velocity - the speed of an object in a particular direction
- Newton's Second Law of Motion - Force equals mass times acceleration; the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object.
- Newton's Third Law of Motion - If one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction on the first object.