# Homework Help: Help with decelleration, acceleration and time!

1. Mar 13, 2009

### djszkoda

Last edited: Mar 13, 2009
2. Mar 13, 2009

### Vuldoraq

Hi, welcome to PF.

You need to use $$v^{2}-u^{2}=2as$$ where u is the initial velocity, v the final, s is the displacement and a is the acceleration. From this you can find s and then find t.

3. Mar 13, 2009

### Carid

You have everything you need.

Imagine two trains running together on parallel tracks. One slows down, stops for a while and then accelerates back to cruising speed. The other one is now a good way ahead. What you have to find is the time seperation between these two trains as they pass through the next station without stopping.