PhysicsQuest

CONSERVATION OF MOMENTUM

THE AIR TRACK

INTRODUCTION

The air track is a tool to study one-dimensional motion with friction virtually eliminated.

The configuration consists of the track itself, air blower, carts and a collection

of accessory pieces. The accessories include rubber band bumpers, wax/pin bumpers, "sails" and other pieces that are easily attached to the carts.

PROCESS AND RESOURCES

Part I. DEFINITIONS

Using your own words  answer the following

questions:

Elastic Collisions

1. Define an Elastic Collision.

2. Discuss the how the concept of elastic

   collisions applies to Newton's cradle (swinging balls).

Inelastic Collision

3. Define an Inelastic Collision.

4. Combine the equations of conservation of momentum

   and conservation of kinetic energy to derive an

   expression for the fraction of energy loss in an

   inelastic collision. Show all your work!

Part II. AIR TRACK SIMULATION

Print the worksheet below, run the simulation

and answer the questions. Show all your work.

CONCLUSIONS.

9. Describe the main ideas learned in this activity regarding elastic and inelastic collisions.

The Coefficient of Restitution is defined in this webpage for the collision between a ball and a racquet.

6. How is the elasticity related to the kinetic energy?

7. What happens to the kinetic energy in an inelastic collision?

8. What are the values of the coefficient of restitution for the

   two types of collisions?

Momentum Lab

TASK

This activity is divided into two parts. In the first part,  you will use the links provided to answer some questions regarding collisions.

In the second part of the activity you will use a computer simulation of an

air track to study the conservation of momentum of elastic and inelastic collisions.

Analize the situation of wearing seatbelts in a car.

5. Discuss how the stopping distance is related to impact force in stretching and

   non-stretching seatbelts.

Go to:  AIR TRACK