Energy efficiency of torsion Catapult

[lovemake1]

Homework Statement

How would you find the energy efficiency of a torsion catapult ? (one i built for project)


I have the Force at which I am pulling the arm.
F = 20N

also the angle from origin to the point of release ( or when the ball leaves the arm)
Theta = 50 degrees

Homework Equations

Energy Efficiency = Energy Output/ Energy Input
E input =

The Attempt at a Solution

i have filmed the trajectory of my catapult using Video camera and logger pro software.
i do have velocity and acceleration in both x and y directions.

But how do i exactly find the Input energy of this particular system?

 

[Andrew Mason]

Homework Statement

How would you find the energy efficiency of a torsion catapult ? (one i built for project)


I have the Force at which I am pulling the arm.
F = 20N

also the angle from origin to the point of release ( or when the ball leaves the arm)
Theta = 50 degrees

Homework Equations

Energy Efficiency = Energy Output/ Energy Input
E input =

The Attempt at a Solution

i have filmed the trajectory of my catapult using Video camera and logger pro software.
i do have velocity and acceleration in both x and y directions.

But how do i exactly find the Input energy of this particular system?

What is the source of energy? What is the potential energy of that source before firing the catapult? What is it after it has been fired?

AM