# Constant Acceleration of a motorist

1. Dec 8, 2008

### devyn

1. The problem statement, all variables and given/known data

A speeding motorist traveling 120 km/h passes a stationary police officer. The officer <i>immediately</i> begins pursuit at a constant acceleration of 10.0 km/h/s. How much time will it take for the police officer to reach the speeder, assuming that the speeder maintains a constant speed? How fast will the police officer be traveling at this time?

2. Relevant equations
These are the equations we have to pull from in class:

Vf=Vi + at
D= Vit + 1/2at2
D=1/2t (Vf+Vi)

3. The attempt at a solution
I fixed the mixed units so that 120 km/h equals 33.33 m/s and 10 km/h/s equals 2.778 m/s2
The officer's Vi is 0.
Distance(D) of the motorist and Distance(D) of the officer should be the same, as well as their times(t).
So, Dm=Do
and tm=to
I've tried solving the above equations for a distance or a time that i can then sub back in, but nothing seems to be working. I just need a little push in the right direction.

2. Dec 8, 2008

### LowlyPion

Write equations for motorist and officer starting at t=0 and apparently x=0 for each.

When the X's equal then the motorist gets his ticket.