# Soft drink bottle using compressed air for thrust to act like a rocket.

1. Oct 22, 2008

### Jessielowe123

Hey! This is the first time I have used this forum so I hope it all goes well and I am sorry if I break any rules on my first attempt.

I have been given a question which I believe will involve quite alot of work, so I thought I would get some suggestions as to where I need to start.

Basically, I have to use a a soft drink bottle as a rocket and determine the range ignoring drag. I have been given:

Bottle Capacity: 1.25 L
Bottle Mass: 50 grams (0.050kg)
Outlet Diameter: 22 mm (0.022m) (Can be reduced to improve performance)
Compressed air
pressure inside bottle: 654 kPa (absolute)

This is purely theory it is not a practical task.

I have then been provided with Bernoulli's Equation:

$$\rho$$gh + 0.5$$\rho$$V^2 = constant

Where p = density, g = 9.81m/s^2, h = height, V = velosity, P = Pressure

I know I will eventually need to incorporate projectile motion equations, Ideal Gas Law and mass flows to find the range. Is there anywhere you can suggest I start as I do not want to go down the wrong path through hours of frustrating equations if it is the wrong way. I just do not know what equation flows onto the next and where to even start.