# Designing an experiment, i no how, just need a formular

1. Oct 29, 2006

### me2

Design a labatory experiment to investigate how the range of a projected object depends on the angle of projectory and find the optimum angle

i was thinking of getting dome tubing, and ataching a preasurises CO2 canister (fire extingiser basicaly), and put something in there to regulate the preasure it fires the projectile with, then just ajust the tube and record the angles of projectory and horizontal displacement etc

so i just woundered if there are any fancy (but usable) formulars i could put in?

thanks

2. Oct 29, 2006

### Hootenanny

Staff Emeritus
If you ignore air resistance the formulae required are elementary. Have you studied any kinematics?

3. Oct 29, 2006

### me2

any wat? nope dont think so (if i have i dont no it by that word) sorry

4. Oct 29, 2006

### Hootenanny

Staff Emeritus
So you have never seen formulae like;

$$s=ut + \frac{1}{2}at^2$$

5. Oct 29, 2006

### me2

that would be a no, although i think i might have done something similar, thanks anyway, ive spoken to a friend n they havent used any formulars so i might give it a miss

thanks for ya time anywayz

6. Oct 29, 2006

### Office_Shredder

Staff Emeritus
Do you actually have to do this experiment?

7. Oct 29, 2006

### me2

nope just plan it

8. Oct 29, 2006

### aeroengphys

Well, if you actually have to create this experiment, there are much easier (and cheaper) ways to go about it. All you need is an inclined plane, a rubber band, and a marble. Attach the rubber band to the end of the inclined plane, put on the marble, and launch the marble from various angles, starting from 0 and going in increments of about 5° until you get to 90. Best of luck.

9. Oct 29, 2006

### Office_Shredder

Staff Emeritus
What I would do (much simpler, and doesn't require pneumatics, which guarantees something will explode, if not accidentally then because you know you're going to want to blow it up at the end and write it off as a lab expense :D), is first, get a tube with one end closed. second, take a plate with a bar sticking through it, and glue a spring onto it so the spring wraps around the bar. Drill a hole through closed end of the tube, large enough for the bar on the plate to fit through, but small enough so the spring can't. Notice you can now pull on the bar, and when you let go, the plate will shoot forward because of the spring (perhaps attach something to the end of the bar so it doesn't fly back out). Using this as a projectile device is much more convenient, because the force is easily calculable based on how far back you pull the bar, so you don't need to hand-wave and say you put a pressure regulator inside of your apparatus

10. Oct 29, 2006

### me2

i like the last idea, but im over half way through writing my original idea up and i dont have the time to start again, n like u said, more chance of blowing something up which reminds me i ought to put that in the safty precautions