Catapults

Objective - To design and construct a catapult to launch a ping pong ball at a target with the specifications given below.

Details:

• Students must work in groups of 3 or 4 people.
  
• What is to be done?
  1. Design a catapult.
  2. Construct the catapult.
  3. Take data and make calculations with your catapult. (you can use data from the official launch on February 18 or use data from your practice launches)
  4. Launch a ping pong ball at the target on launch day ( Monday, February 18)
  5. Turn in your extra credit report. (Wednesday, February 20)
  
• Grading - You will receive a maximum of 20 points extra credit which will be added to you homework totals. You will receive points for building the catapult (8 points), how close your ball was to the target (2 points), and your report (10 points).

1. Design a catapult that will launch a ping pong ball into a container 4 meters away. The set up is shown below.

*Catapult must have an automatic launch mechanism and be an actual device (you can't just pull back on a sling shot for example).

2. Construct the catapult. Try to limit the size of the catapult. Remember it only has to launch the ping pong ball or egg about 4 or 5 meters. Use any kind of materials you can get your hands on.

3. When your catapult is finished you need to launch a ping pong ball and make measurements. You should be able to measure the following: time, change in height, and range. From this data you should be able to calculate the following (we'll be studying projectiles in class to help you with this part):
a. inital velocity in the y-direction
b. initial velocity in the x-direction
c. initial velocity (magnitude and direction)
d. final velocity (magnitude and direction)
f. maximum height
e. acceleration of ball while being launched
f. force on ball while being launched

4. On launch day you will need to launch your catapult for the class and try hit the target. Every one will get 2 tries and then, depending on the number of catapults, perhaps 1 or 2 more. How close you are to the target should then be recorded in your report.

5. Your report should consist of a
page 1 - title page (1 point)
page 2 - diagram (or picture) with materials used and dimensions (in centimeters) shown on the diagram (3 points)
pages 3 & 4 - data & calculation page(s)(4 points)
page 5 - all calculated results in a nice table and a summary/conclusion paragraph (2 point). You only need one report for the group.