Two cars, one accelerating: how far does Tina travel before passing David?

[jdhutto]

Kinematic problem help!

Homework Statement

David is driving a steady 31.0 m/s when he passes Tina, who is sitting in her car at rest. Tina begins to accelerate at a steady 2.80 m/s^2 at the instant when David passes.

How far does Tina drive before passing David?

What is her speed as she passes him?

Homework Equations

The Attempt at a Solution

I know that there is two different cars moving seperatly and they will need two different equations, but I am not sure exactly how to go about this one?

 

[mgb_phys]

For the steady car s=vt, for the accelerating one s=ut+1/2at^2

 

[jdhutto]

OK I am just not sure what do with the equations, and what is s representing in these equations?

 

[Ekpyrotic]

...and what is s representing in these equations?

's' is the standard abbreviation for displacement.

If you are finding it hard to use the equations directly it's probably because you don't quite know what you're heading for. This may help, or it my not, if both car's movement were mapped onto a distance-time graph would they cross? If so, what does this mean in respect to the equations.

~ Ek.

 

[jdhutto]

What does u represent in these equations and i am having trouble finding time, what steps do I need to find this?

 

[mgb_phys]

There is a sticky describing the equations ( with better latex formatting).
Generally:
s = distance
t = time
a = acceleration
u = initial velocity
v = final velocity