Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Which Catapult would work best?

  1. Sep 14, 2006 #1
    I'm not sure if I posted this in the right thread, if not feel free to move it.

    I have been assigned to build a catapult as my physics project. I have researched a bit and saw some examples. The main purpose of the catapult will be accuracy.

    First of all, I wanted to ask you experts which of the following catapult systems will be more accurate?!

    1. We use a weight as the source of energy. Think of it as a pendulum. The weight at the bottom of the beam moves back, the beam will go forward and the projectile at the top will be launched.

    2. We use a spring rather than the weight. The spring pulls the beam to itself, then the beam will come to a sudden stop and cause the projectile to be launched.

    The only thing that really matters is the accuracy here. I need to be able to hit a target within 8 meters of the catapult.

    Another question is what effect will it have to extend the beam? Will it cause more velocity?! I was playign with this catapult idea and this idea popped that it would be cool to have the arm actually have a variable length. Will that help at all? Or is it just a waste of brain cells (I know I need to do lots of calculations)?

    Also if I were to use the spring as teh source of energy, how can I calculate the force of it and all?! I mean with teh weight it's just the pendulum...easy. Butthe calculations with the spring are kind of foggy in my head. Can someone shine a light on that too?

    Any help is appericiated :smile:
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?