# Physics help 2

posted by
**tracey** on
.

I've asked the question "what is the fundamental equation to find the speed of a rocket." That's what I am having problems with because there are more than one. How do I know which one is the preferred equation used?

The preferred equation is the one that suits what you are doing.

I would go with the impulse equation:

Force*time=mass*changeinvelocity