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Q:
When using a catapult to launch a hacky sack, how will the number of rubber bands as the perpulption unit affect the distance the hacky sack will travel? I know when I used more it went farther, why? Also, do you have any ideas that could change my results? Have you attempted a similar experiment? thanks
- Chris Graebe (age 11)
Signal Hill School, Belleville,IL 62223
A:
The idea behing your catapult is that the rubber bands will be
stretched and then pull down on the main arm to launch the hacky sack.
When you add more rubber bands, it requires more force to pull the arm
down. The energy you put into pulling the arm down is held by the
rubber bands until you let it go. Then, all the energy in the rubber
bands goes into making the sack fly into the air. So in the end, more
rubber bands will make the sack fly farther. The easiest way to change
our results will be to change the number of rubber bands or the object
that you are throwing. Be careful not to break anything. You can also
change the arm of the catapult, but that takes a little more work.
I haven't made a catapult before, but some of my friends made
another thing called a trebuchet. A trebuchet is similar to the
catapult but insted of using rubber bands, it uses large weights. I
couldn't find any pictures of the one they made, but you can see what a
trebuchet looks like at
Trebuchet.com.
Adam
(published on 10/22/2007)
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