I was hoping someone out there could offer me much needed insight on my high school Physics project. I had to build a trebuchet and now I have to write a report about it. I have struggled with this and put much time into try to figure the velocity of the projectile (tennis ball) as it leaves the trebuchet (would this also be the velocity in x dir. b/c its constant?) I was using the equation mgh= 1/2mv^2 and solving for v. (Since m cancels, not needed, and I was using h as the distance the counter weight falls)(All the hint that was given by my teacher was that something might need to be added to the equation, but then how could figure in mass c.w. , mass of ball, h of c.w. etc.) However this velocity is way too slow to give me the estimated distance that I achieve. I have an actual distance of about 14 m. I know I could reverse solving it using my time but I need to use the energy equation to show my teacher that I can estimate the distance it goes without actually measuring the distance from the launch. I also know that from the energy equation above the velocity should be higher than the actually velocity because of energy lost in various aspects and in flight. Variables t(flight time) =.9 s h(how far c.w. falls)= .406 m g(gravity)= 9.8 m/s2 Using stuff above I calc. a v of 2.82 and from that get a *clalculated* distance of 2.53 m by multiplying t by v (see the problem ) Sorry for the long post, but hopefully you can see my frustration with the matter. (P.S. I am in just basic/normal high school Physics, so please keep it below college level) Thank you to all who read and/or respond Need any more info please let me know and will get info ASAP !