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Module 2

1. Module 2

1.10. Lesson 2

Physics 30 Module 2 Lesson 2

Module 2—The Conservation of Momentum in Isolated Systems

Lesson 2—Kinetic Energy and Collisions

 

Get Focused

 

Two photos are shown side by side. The photo on the right shows a young man about to shoot a cue ball on a pool table toward a solid purple "target" ball. The photo on the left shows a blue car that has just rear-ended a grey car.

left ©Frances Twitty/iStockphoto

right © Arthur Kwiatkowski/iStockphoto

What happens when a moving object strikes a stationary object? The answer to this question depends very much on the characteristics of the system of objects that are colliding.

 

Consider the case of the cue ball striking the purple ball on the pool table in the photograph on the right. If the collision occurs along a straight line, and spinning is kept to a minimum, then the cue ball will likely stop and the purple ball will move with very nearly the same velocity that the cue ball had prior to impact.

 

Would a similar chain of events occur when the blue car rear-ends the grey car in the other photo? In other words, would the grey car leave the point of impact moving with very nearly the same velocity of the blue car prior to impact? How does the system of the two cars differ from the system of the two balls on the pool table? What is the significance of the fact that the two cars undergo a permanent change in shape but the pool balls do not? The answers to these questions require you to consider the changes in kinetic energy that occur when a collision occurs within a system of objects.

 

In this lesson you will explore elastic and inelastic collisions within the context of the following questions:

  • How can the kinetic energy of the objects in a system before and after a collision be used to categorize the type of collision?

  • What is the fundamental difference between an elastic and an inelastic collision?

  • In a collision between two automobiles, is it better for the occupants if the collision is elastic or inelastic?

Module 2: Lesson 2 Assignments

 

Your teacher-marked Module 2: Lesson 2 Assignment requires you to submit a response to the following:

  • Lab—LAB 1 and LAB 2

  • Assignment—A 1, A 2, and A 3

You must decide what to do with the questions that are not marked by the teacher.

 

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.

 

You will also continue to add to your Module 2 Project that you started in Lesson 1 and saved in your course folder. The finished project will be submitted to your teacher for marks once you have completed Module 2.