1. Trebuchet Calculations

2. Calculate the counterweights mass 
English lb. / 32.2 ft./s2 = 7.76 slugs 
Calculate the mass of the projectile 
English – 6lb /32.2 ft./s2 = .19 slugs

3. Calculate the torque on the counterweight
T = F x L
English - 250lb x 4.5ft = 1125 lb.ft
Calculate the torque of the projectile
T= F x L
English – 6lb x 8ft = 48 lb.ft

4. Calculate the potential energy of the counter weight
EP = w x h
EP = m x g x h
English EP = 250lb x 4.5ft = 1125 lb

5. Calculate the potential energy of the projectile
EP = w x h
EP = w x g x h
English EP = 6lb x 6.5ft = 39 lb

6. Calculate the velocity of the projectile
English v = d/t so v = ft./t so 32.8ft / 1.75 sec = ft./s
Calculate the acceleration of the projectile
English aave = vf – vi / t2 – t1 or a = ft./s – 0ft/s / 1.75s – 0s =10.71 ft./s

7. Calculate the kinetic energy of the pumpkin
English EK = ½ w/g v2
English ( .5 x (6lb / 32.2ft/s2)) x (18.74 ft./s)2 = lb

8. Calculate the efficiency of the trebuchet
Efficiency = Workout / Workin x 100%
Work = T x Ɵ
T= torque Ɵ = Angle moved through x radians
English
Workout = projectile torque x (degrees x rads) Workin = Counterweight torque x (degrees moved x rads)
Wout = 48lb.ft x (60°x rads) = 50.4 lb.ft
Win. = 1125lb.ft x (60° x rads) = lb.ft
Eff = 50.4 lb.ft / lb.ft x 100% = 4.26%