Determining arm length of catapult

AI Thread Summary
To determine the arm length of a catapult designed to launch a 2-gram ping pong ball 1.5 meters using a 3/4" paper clamp as the energy source, focus on the principles of torque and angular acceleration. The catapult operates as a first-class lever, with the fulcrum positioned in the middle. The key is to calculate the tangential speed of the arm rather than centripetal acceleration, as this relates directly to the required launch distance. Understanding the relationship between torque and the arm length is crucial for accurate calculations. Properly applying these physics concepts will enable the successful design of the catapult.
ArrowHeart
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Hi, I have a big problem...
I got a project on building a catapult. Easy, right? WRONG! We are supposed to determine the arm length without trial and error and I have no clue what to do. Please please help!

Catapult is supposed to be built with 3/4" paper clamp as the only energy source and it must project a 2gram pingpong ball 1.5m. The catapult is a classic 2nd class lever. How would I calculate the arm length?
 
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It's all about torque.
 
ArrowHeart said:
The catapult is a classic 2nd class lever. How would I calculate the arm length?
Don't you mean a 1st class lever? A catapult has the fulcrum in the middle.

AM
 
Sorry, I mis-typed it. It is a first class lever.
How it is torque related? I tried to determine the centripetal acceleration, it didn't work out very well -_-'
 
Last edited:
ArrowHeart said:
How it is torque related? I tried to determine the centripetal acceleration, it didn't work out very well -_-'
You don't need to worry about centripetal acceleration. You are concerned about the tangential speed of the arm, which is a function of the angular acceleration or torque.

AM
 

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