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?