I'm a physics teacher trying to build some lab equipment to save my school some money. The link below shows a basic drawing of 2x4's set up to mount a tennis ball launcher for dogs on top. The hinge at the back lets the top board swing up like an alligators mouth. It does this to allow launching at different angles so students can practice and understand projectile motion in 2 dimensions.My question is this: What kind of hardware should I be looking for to make this setup (with the hinge) swing from 0 to 45 or so degrees and be able to lock it in place? This would help students launch multiple times at the same angle.I wandered around a lowes for about an hour and the staff was sadly unable to help? I'm trying to keep the budget within reason. A similar setup that launches marbles costs about 90 dollars per launcher from commercial vendors, I'm at about 40 dollars to build 4 of them thus far.Thanks in advance for any help...http://ift.tt/2DO1shH via /r/DIY http://ift.tt/2DRQRGA
