lol but we're going of his topic
if its for maths this is what you need to put down:
1 fairy tells 5 spirits to load 1 ball on to 1 catapult and then 2 fairys let the catapult go shooting the paintball down the barrel at 300fps.
see now thats maths.
i made this up as i went
F=MA
force = mass x acceleration
you know that the ball is moving at 300fps and the gun is fireing at 15 bps (lets keep the maths reasonably simple)...this will allow you to work out the acceleration.... convert this to meters per second square
weigh a ball to get the mass in N
then you can calculate the force on the ball when the air hits it
(this wont be exact as we are assuming that 15bps is the max output, but your teacher will be happy with the maths)
another reasonably easy one to work out is how far will the ball travel before it hits the ground.
assume a hight (measure it) you are holding the gun and assume that you are holding it horizontal....you know the speed the ball is moving horizontally and you can use affect of gravity to work out how long the ball will take to drop to the groud.......then use this time to work out how far the ball will travel in this time. if you want to get a little more involved you can do the same thing but assume the barrel is angled up at 5*.
dont try to work on the maths of what is actually going on in the gun...far too complicated for school stuff, unless you are doing A-level physics just stick to the ball rather than the gun and the teacher will love it,
That IS the simple version.cant we just simplyfy the maths a bit more (got a d in my gcse's )