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# Building a catapult for physics class.

10 replies to this topic

new soul

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Posted 05 October 2002 - 01:35

i have to build a catapult over the weekend, and i don't know where to start. Can anyone give me links so catapult resource sites? Like, sites that have catapult designs, in which i can build? And preferably, a catapult which won't cost too much to build. Plz? thanks.

### #2 Goalie_CA

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Posted 05 October 2002 - 02:12

I'm an engineering student so i could probably give you pointers.

-what level of physics are you at?

I would really recommend doing some simple newtonian calculations like trajectories, force, acceleration, velocity, mass, energy, or whatever you need to get the object flying.

If you don't know how to calculate any of those then taking a ruler and flinging an eraser is probalby good enough (seriously, something simple like that may work) like take a large piece of bendable plastic and stick it to something.

new soul

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Posted 05 October 2002 - 02:20

umm, i'm taking physics H. the one offered in high school. And i would do sumthing simple, but it has to launch a golf ball, and i sort of want to win the "farthest golfball launched" position.

Originally posted by Goalie_CA

I'm an engineering student so i could probably give you pointers.

-what level of physics are you at?

I would really recommend doing some simple newtonian calculations like trajectories, force, acceleration, velocity, mass, energy, or whatever you need to get the object flying.

If you don't know how to calculate any of those then taking a ruler and flinging an eraser is probalby good enough (seriously, something simple like that may work) like take a large piece of bendable plastic and stick it to something.

### #4 Goalie_CA

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Posted 05 October 2002 - 02:34

disclaimer: i'm in engineering but "modern", basically anything high-tech, engineering and only 1st year.

A nice long piece of stiff but bendable platic shoud do the trick. the launcher is up to you. perhaps a cup or something.

with grade 10 math and grade 11 physics knowledge you should be able to do some math to figure out the optimal angle.

### #5 Hypercube

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Posted 05 October 2002 - 04:05

I'd play around with the length and angle just to ensure the longest distance. Try 45 degree angles

### #6 Mr magoo

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Posted 05 October 2002 - 16:42

big elastic band. piece of wood, and a piece of wood coming of that inital piece of wood -to hold the golf ball.

```

( ) - ball

- support / arm

_______________________________

```

im sure you can figure something out from that

### #7 Goalie_CA

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Posted 05 October 2002 - 16:44

Wouldn't that make it a slingshot and not a catapult.

I think the best angle would be something more like 50 to 55 degrees.

### #8 Hypercube

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Posted 05 October 2002 - 17:00

Originally posted by Goalie_CA

Wouldn't that make it a slingshot and not a catapult.

I think the best angle would be something more like 50 to 55 degrees.

In theory, the projectile trajectory is best at 45 Degrees. Look it up in your books.

### #9 Hummer

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Posted 05 October 2002 - 17:03

Originally posted by Hypercube

In theory, the projectile trajectory is best at 45 Degrees. Look it up in your books.

you're right it is 45 degrees

new soul

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Posted 05 October 2002 - 17:36

hey, thanks for the info.

### #11 Goalie_CA

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