How do I build a catapult?

Question

I need to make one for physics and I'm not good with science or engineering. I have no idea where to start. I have about 3 weeks to make this thing so any help would be greatly appreciated.
It needs to launch a ping pong ball 4 meters into a basket with sides about 18 inches high.
Please include websites with designs if possible. I have **no** money to spend on books and very little for materials.

Answer 1

Thats totally easy:

Put 2 longer nails in a board, and use a rubber band between them.
Twist the rubber band till its getting tighter and then stick in a plastic spoon as the catapults arm to carring the ping pong ball.
Then adjust the catapult - twist the rubber band to get tighter or less tight, or adjust the length of the spoon till the ball gets the right velocity.

You can also add some gimmicks for extra points:
Like put a wire or rope between the top of the 2 nails, to stop the spoon-arm hlf way from hitting the ground on the other side, you can use wire to make a hook that holds down the arm until you release it by pulling back the hook...attach tiny wheels to it and paint it, to make it look like a tiny medieval war machine..
..just have fun :)

Answer 2

Look around the garden for a fork in the branches. you need the fork to be about half an inch think, cut it so it looks like the letter "Y". get an old car/bike tube and cut strips of the tube about 1/2" wide and about 12-14" long. you will need 2 strips. Now cut some strips about 3mm wide. Put each 1/2" strip on the top of each of the top forks of the 'Y" and bind them tightly with the small strips. Now cut the tongue out of a shoe in an oval shape of about 3" by 1" and cut two small holes in each end. feed the ends of the 1/2" strip through and double over and bind. And you have a catapult which cost nothing.

Answer 3

OK I'm not an catapult guru but I'll try

first safety do every thing that has potential energy w/ safety OK


you can get hurt or hurt your team OK


OK fulcrum is Th biggest thing then propulsion either
rubber bands 1
rope wire / string
then you have to work out the potential force and work need to propel the object and like a race car don't for get to make a good stop to stop the arm when it finishes it's travel distance
it should be a blast during trial and error

i suggest enclosure when your done to massively protect everyone in the area

I'm not gonna give you a on line link cause i would do it w/ out one my self but DO look @ examples and derive yours from them DO NOT COPY try for originality it will have an response i Think you will like from your teacher or professor good luck

Answer 4

get some industrial strengh giant rubberbands and put them between two trees

Answer 5

just buy one. It is a lot easier
tell people u made it

Answer 6

Try some of these.

Answer 7

try this:

Answer 8

first get one cat...........