# Homework Help: Constant acceleration of rocket car

1. Sep 12, 2011

### andyman21

A "rocket car" is launched along a long straight track at t=0s. It moves with constant acceleration a1=1.2m/s2. At t=2s a second car is launched with constant acceleration a2=7.2m/s2.

At what time does the second car catch up with the first?

How far down the track do they meet?

I always have problems with these problems because you need to use the kinematics equations and i get confused. Any help would be greatly appreciated.

2. Sep 13, 2011

### wukunlin

at constant acceleration, the distance travelled with respect to time is given by:
$$d = \frac{1}{2} a t^2$$
note that sometimes the equation needs to be modified to fit the context of your problem

basically your question requires you to produce two of these equations and solve for t and d