# Homework Help: Constant Motion Vs. Acceleration

1. Oct 2, 2011

### jessicayin22

1. The problem statement, all variables and given/known data
A reckless motorcyclist drives past a school zone at a constant speed of 15 m/s , where the speed limit is only 10 m/s. at the same moment a police officer chases the motorcyclist from rest and accelerating at the rate of 3 m/s?
a. how fardoes the police travel before catching up to the motorcyclist?
b. how much time does it take the police car to catch up to the motorcyclist?
c. how fast is the police car traveling when it catches the motorcyclist?
2. Relevant equations
V(bar)=d/t, a= deltaV/t,

3. The attempt at a solution
okay, so i know that displacement is equal to each other, i've set the equations equal to each other and then solved for t....??

Last edited: Oct 2, 2011
2. Oct 2, 2011

### PeterO

You have a question mark, but have not actually asked a question.

I assume you want to know when the policeman catches the motorcyclist.

You could draw/sketch velocity time graphs of the situation and instantly see the answer.

Displacement of the reckless one is 15t

Displacement of the policeman follows "the equations of motion with constant acceleration" and one of them is really appropriate.

The displacements will of course be equal.

3. Oct 2, 2011

### jessicayin22

i set the equation and found out T= 18.75? ..... but it doesnt make sense since the displacement eauals 140.625m