Catapults

Objective - To design and construct a catapult to launch a golf ball or egg and be able to hit 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 November 30 or use data from your practice launches)
4. Launch golf ball at the target on launch day.
5. Turn in your extra credit report.
• 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 launch was to the target (2 points), and your report (10 points).

1. Design a catapult that will launch a golf ball into a container 10 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 golf ball or egg about 10 meters. Use any kind of materials you can get your hands on.

3. When your catapult is finished you need to launch a golf ball and make measurements. You should be able to measure the following: time (in seconds), change in height (in meters), and range (in meters). 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)
e. maximum height
f. acceleration of ball while being launched
g. 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 1 try and then, depending on the number of catapults, perhaps 2 or 3. How close you are to the target should then be recorded in your report.

5. Your report should be word processed (except for calculations) and consist of a
page 1 - title page (1 point)
page 2 - nice diagram of catapult (or a good picture) with materials used and dimensions of catapult (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.