Projectile Motion Phet Simulations Physics 2010

Name:                                                                      Projectile Motion

Go to  http://phet.colorado.edu/en/simulation/projectile-motion

and click on Run Now.

1. Go to the web site.

1. For the first part of the activity you need to focus in on certain aspects of what this simulation can show you, so please set the variables on the simulation to the following values:

·         keep air resistance off

·         drag the cannon so that it is above the ground.  A good distance would be to raise it up to about the middle of the screen.

·         Set the angle of the cannon at 270 degrees. 

·         change the initial speed to 0 m/s

·         Leave air resistance off and

·         leave the mass and diameter at their default settings. 

Mass = 2kg and diameter = 0.1m

If you set all of the conditions above correctly you will see the projectile behave as if it were just dropped.

1. You and your partner should fire the projectile several times and since we want to compare data for different conditions your group will need to make a data table like you see below so you can record your data for every time you fire the cannon.

1. Having fired the cannon several times with out changing any of the conditions discuss with your partner any changes you observed in the variables the simulations shows you. As a group write a brief description of what this tells you about what should happen to an object if it is always dropped from the same height?
2. Next keeping the height the same and setting the angle to 0 degrees vary the initial speed and fire the cannon several times recording the data for each firing in your data table. While you are gathering your data look for relationships between the following:

·         initial speed of the projectile and the range of the projectile

·         initial speed of the projectile and the time of the projectile in the air?

·         initial speed of the projectile and the height the projectile moved downwards?

1. Working with your partner develop and write down several general rules that you can use for projectile motion.  An example of a general rule might be:

EXAMPLE: Whenever you increase the initial velocity of a projectile that is launched horizontally, the time the projectile is in the air will always __________.

1. For this part of the activity, set the simulation to the following conditions:

·         leave the mass, drag coefficient and altitude at their default settings, Mass = 2 kg, Drag coefficient = 1 and altitude = 0 m,

·         vary the diameter of the projectile,

·         turn air resistance on and off for each diameter used,

Then fire the cannon several times making observations on how the changing diameter affects the flight path of the projectile. Also note how air resistance being turned on and off changes the affect of the changing diameter.  Please note that you can make the projectile so large it fills up the entire screen so you might want to keep your diameters smaller then 10 m.

1. With your partner write down a description of what happens to the flight path of a projectile while changing the diameter of a projectile with air resistance on, and compare that to what happens when air resistance is turned off?