Motion with constant acceleration

1. Feb 22, 2009

Susanem7389

I'm having trouble finding the equation.

Two cars are traveling along a straight road. Car A maintains a constant speed of 80 km/h and car B maintains a constant speed of 110 km/h. At t=0, car B is 45 km behind car A. (A) How much father will car A travel before car B overtakes it? (B) How much ahead of A will B be 30 seconds after it overtakes A?

2. Feb 22, 2009

LowlyPion

It's all constant speed,

All you have to know is that V*t = d

3. Feb 22, 2009

Susanem7389

I'm still not sure how to figure it out.

4. Feb 22, 2009

LowlyPion

Look at the differences in speed.

How long to make up the difference in distance?

5. Feb 22, 2009

slider142

Try writing the distance from the position that car B is at t=0 as a function of time (In other words, place your origin at that point. It may help to draw a simple diagram).
For example, dB(t) = vBt = 110t (m). Try finding dA(t). Since you are measuring both distances from the same origin, you want to find the time t that the functions are equivalent.

Note that this is a very rote approach. Try LowlyPion's intuitive way first.