Why Is My Trebuchet's Initial Velocity So High?

[skylarr]

ok i had to build a trebuchet for high school and i can't seem to get a decent value for the initial velocity please help. i used a 60 pound counter weight (27.2 kg) a tennis ball to launch (.057 kg) and the counter weight drops about 1.3 m when it is launched i used the equation mgh = 1/2 mv ^2, but i got 110 m/s pleas help this is due tommmorow.

thanks

 

[prasannapakkiam]

Okay, I have no idea how you got 110. Anyway this model is very simplistic but still correct. Remember that the counterweight does not matter with your set of equations. Anyway the answer (according to your assumptions) should yield:
therefore: 1.3*9.8=.5*v^2
therefore: v=SQRT(2*1.3*9.8)