# Homework Help: Acceleration with Velocity Problem.

1. Mar 1, 2013

A boy is running a a constant velocity of 3.0 m/s [E] and passes his father who is standing still. The father immediately starts to chase his son with a constant acceleration of 1.5m/s at the instant his that his son reachers him

How long does it take the father to catch his son?

So to find time. I did

T= vf - vi/aav

Vf is final velocity (3.0-0)
Vi is initial velocity (0)
Aav is average velocity (1.5)

I got 2 Seconds? But the correct answer is 4? How?

Last edited: Mar 1, 2013
2. Mar 1, 2013

### haruspex

You calculated the time it would take the father to reach the same speed as the son. But he will still be some way behind the son.

3. Mar 1, 2013

so what do I do though...

4. Mar 1, 2013

### haruspex

Write equations for how far each will travel in time t after the son passes the father.

5. Mar 1, 2013

### Equilibrium

at the instant his father catches his son, they all have the same distance from since the son passed his father, hence:
$$d_{father}=d_{son}$$

continue here