The problem statement, all variables and given/known data We need to find the mass of the counter weight needed to make our projectile go a certain distance. Height = 22.5cm (The height of arm off the ground) Distance needed to travel = 1m/100cm and and 50cm Angle above horizontal = 32 degrees Projectile mass (small ball) = 125 grams Counter Weight mass = WHAT WE ARE CHANGING We don't know velocity or anything else like that. How can we find out how much mass to put on the counter weight to make it travel a certain distance? Also please give equations/units. This is really bugging me. I tried many things and formulas but nothing seems to be working for me. What I've tried I tried using a lot of formulas but so far all my stuff is theoretical. I know I can find velocity using distance/time but I can't do it like that because I still haven't gotten it to launch that far. I have stumbled upon lots of formulas and tried some from this PDF: Code (Text): [PLAIN]http://www.algobeautytreb.com/trebmath35.pdf [/PLAIN] [Broken] But a lot of the stuff is too advanced and isn't specifying units. The one formula I did try was this: Range = 2 * (Counter weight mass/projectile mass) * h. Height = the height the counter weight falls to. However, the result's I'm getting seem very off.