Question regarding distance traveled by a trebuchet

[permapoop]

Homework Statement

I need to find the distance traveled by a trebuchet. We were assigned to design and create one to launch a water balloon of roughly a mass of \approx50 grams. We are not allowed to test it, but must make a prediction of how far it would travel by using physics.

The Attempt at a Solution

I was trying to factor in rotational force and the transferring of potential to kinetic energy. The potential energy within the counterweight of the trebuchet would transfer the potential energy to kinetic energy so that the balloon can be launched. And I was thinking of using the Conservation of Energy to solve for the velocity and assume that the angle it launches at with the horizontal is 45 degrees.

Am I doing this correctly? Or is there a special solution on how to do it?

 

[Mark44]

The distance traveled by the trebuchet is generally zero, unless someone is moving it
In your case, you want to calculate the distance the water balloon travels.
Other than that, your plan seems reasonable. Of course, it ignores the energy wasted due to friction, but you should be able to get a reasonable estimate for how far the water balloon travels.

 

[permapoop]

How would you factor in the rotational force in it though?
I'm still only a beginner in physics so I can't really figure it out.

I understand how to use the conservation of energy but I'm not sure if the rotation will affect it. Is it just mgh + 1/2mv² = mgh + 1/2mv²?

 

[wbandersonjr]

Yes conservation of energy is a good way to look at this problem. Yes, rotatino plays a part in this. Do you know the equation for rotational kinetic energy? Your conservation of energy equation will include potential, translational kinetic, and rotational kinetic energies.