# Homework Help: Hardest AP PHysics lab EVERRRRRR

1. Nov 10, 2004

### the4thcafeavenue

now guys, i need your help. in this lab, i am making a rocket with a 2 litter soda bottle with water inside, and air will be pumped in so that rocket will fly up. i need to determine a set of equations that will describe the THRUST of my rocket as a function of TIME or MASS or both. we can use M*(delta)v=dm*Ve and Vf-Vi=Ve*ln(Mi/Mf) and whatever other equations will help. Thrust= M(dv/dt) or Ve*(dM/dt).

2. Nov 10, 2004

### Justin Lazear

$$F = \frac{d}{dt} mv$$
$$F = \frac{d}{dt}\left( mv\right) = v\frac{dm}{dt} + m\frac{dv}{dt}$$