PhysicsQuest

CONSERVATION OF ENERGY
INTRODUCTION

You are in Six Flags over Texas waiting  in line to try Batman the Ride roller coaster.
You boarded the roller coaster and now you're barreling down the track at 60 miles per hour, taking hairpin turns and completing death-defying loops.
Your heart is in your throat and your stomach is somewhere near your shoes! You are having so much fun!
Then you suddenly remember that the laws of PHYSICS are behind all the rides in the amusement park!

You've learned in class that the coaster has no engine. The car is pulled to the top of the first hill at the beginning of the ride, but after that, the coaster must complete the ride on its own. You aren't being propelled around the track by a motor or pulled by a hitch. The conversion of potential energy to kinetic energy is what drives the roller coaster, and all of the kinetic energy you need for the ride is present once the coaster descends the first hill.

In this PhysicsQuest  you will learn the principles of conservation of energy that allow you to enjoy fun and safe roller coaster rides. 
TASK

You will be given a series of questions and various links to Internet sites that will help you answer the questions.
By the end of this PhysicsQuest you will have a better understanding of the factors that have an effect on the total mechanical energy of an object.
PROCESS AND RESOURCES

Part I. INTERNAL vs. EXTERNAL FORCES

In class we distinguished between conservative and non-conservative forces. The author of this site categorizes these forces as internal and external.

1. What is the factor that determines the categorization of the forces?

2. Name three types of forces for each internal and external categories.

3. What happens to the total mechanical energy when an object is
   acted upon by  internal forces?

4. Select two examples in which  the only forces acting upon the
   object are internal forces and explain how the energy storage
   changes.

5. What happens to the total mechanical energy when an object is
   acted upon by external forces?

6. Select two examples in which  the only forces acting upon the
   object are external forces and explain how the energy storage
   changes.
Part II. PROBLEM SOLUTION STRATEGIES

Go to the bottom of the page and read the paragraph right before the PRACTICE EXERCISES.

7. Write three questions that you should ask before trying
   to solve a problem involving conservation of energy.
Part III. BAR CHART ILLUSTRATIONS

8. What is an energy-bar chart?

9. What does the length of the bar represent?

10. Scroll down to the section: Check your Understanding.
For the five situations:
- Identify the system
- Draw energy bar charts/energy flow diagrams:
Part IV. STOPPING DISTANCE

11. Hot Wheels car problem
    Use the simulation to answer the five questions.
- Write down the data and the energy equation
- Solve and calculate the unknown

Take a look at the animation depicting cars at three different speeds. You can observe that the red car is traveling twice as fast as the green car and that the blue car's speed is three times faster than the green car's speed.

12. What conclusion can be drawn regarding the stopping
     distance and the speed of the car? Explain your answer
     using equations to analyse the situation.
Part V. ENERGY TRANSFORMATION IN ROLLER COASTERS

13. Explain in detail the energy transformation on a roller coaster.
     Be careful to use your own words.

14. Why is air resistance neglected when calculating energy
     transformations in roller coasters?
Part VI. PROBLEMS

15. Child in sled problem
    Use the simulation to answer the five questions.
- Write down the data and the energy equation
- Solve and calculate the unknown

Problems:

16. Solve problem 9.
Copy the diagram and show ALL your work for each
section (A to I)

17. Solve problem 11.
Copy the diagram and show ALL your work for each
section (B to E)