Free Fall Frenzy: Penny Myth Busted?

We recently viewed the Mythbusters "Penny Drop" episode. If you missed it in class or wanted to view it again, you should be able to view it at one of the following two links:

• MetaVideo blog


• DailyMotion.com

The episode tested out a physics free fall question we had discussed and calculated in class:
Can a penny dropped from the Empire State Building kill a person?

Knowing only the height of the Empire State Building (381 meters) and that acceleration due to gravity affects all object at a rate of 9.81 meters per second (we round up to ten to make calcuations easier), we calculated that the penny would fall for 8.73 seconds if we didn't factor in friction due to air resistance (which results in objects having a terminal velocity), and that it would hit the ground at a speed of 87.3 meters per second.

If you missed it in class, watch the video, answer ALL of these questions, hand it in and it will count as an extra quiz grade. This offer applies to students who viewed the video in class as well.

Mythbusters Penny Drop Video Questions:

1. According to the show, what is the terminal velocity of a person?
2. What happens to the pennies when the skydiver releases them?
3. What top speeds do their “complex” calculations predict as the terminal velocity of a penny?
4. How does Adam test this prediction?
5. What device does Jamie use to accelerate the penny to that speed?
6. What should Jamie have done before testing the device for the first time?
7. How long does it take the penny to travel the three feet from the device to the concrete block?
8. What velocity do they actually use for their experiment?
9. Why is ballistic gel used to build the Norma, the test dummy’s head?
10. Where do most coins thrown from the observation deck of the ESB end up?
11. According to the experiment, can a penny traveling at terminal velocity penetrate concrete or asphalt?
12. According to the experiment, can a penny traveling at terminal velocity penetrate a human skull?
13. From how far away is the penny fired at Adam’s hand? Does it break the skin?
14. What device do they use to find out how fast a penny has to go to do serious damage?
15. What speed does the penny reach? How many times the speed of sound is that?

If you cannot view the video, ask Mr. Barkan to bring the DVD player at lunchtime and you can view it then. You MUST ask in advance and you MUST allow at least 20 minutes to view the video.

The Plane Truth

We recently used the launching of paper airplanes (we used index cards in class) to develop our concept of acceleration.

Paper airplanes are wonderful tools for illustrating many physics concepts, but the most fun is from making them and flying them.

We will be having an indoor competition for paper airplanes in two categories:

1) Distance/Displacement: Whose plane can go the furthest?

2) Duration: Whose plane can stay in the air the longest (the world record for this is 27.6 seconds).

The Rules: (check back here before you begin your project as the rules below may be changed)

• All work must be done on your own time, as an individual or as a team (you choose your team, maximum of four people).


• You may use only one 8.5 x 11 inch sheet of paper. The paper may be folded, cut or torn, but you are limited to that one sheet. Make sure you include identifying markings on your plane.


• You may use one paper clip and a small amount of adhesive tape (scotch tape or masking tape) in the construction of your plane.


• You must build two planes: one to fly and one to show how it was constructed.


• you may not use anything other than your hand/arm to lauch the plane.


• You will be allowed three attempts.


• Distance/Displacement will be measured as a direct line from the launch point to the point where the plane's motion stops, no matter which direction the plane traveled in its journey.


• Duration will be timed with a stopwatch.

The deadline will be announced (and published here) shortly. For extra credit, construct your best paper airplane and write a brief (two to four pages, with diagrams) report on one physics concept that can be explained and demonstrated using a paper airplane (not including acceleration). Be prepared to demonstrate this to your class. Prepare a summary handout or activity guide along with your presentation. Be sure to cite any and all information sources used and please, please see me before you begin so we can be clear on what is expected. Please leave a comment below if you intend on doing this.