# Homework Help: Collision point of two objects

1. Mar 9, 2010

### tassie

1. The problem statement, all variables and given/known data
Object A is at the origin and must intercept object B.

Object B begins at coordinates 901.3x - 5371y + 591.4z and is travelling in the positive x direction at 6 units per second.

Object A has a maximum speed of 12 units per second.

How long will it take for A to reach B ?

2. Relevant equations

Directional cosines may be useful here.

3. The attempt at a solution

I have only been able to determine a velocity vector for A in order to reach B's initial position and have no idea how to factor in that B has its own velocity vector which is impacting on the position.
What I have for A's velocity to reach B's starting point is 1.974x -11.76y +1.295z where it then takes 456.68 seconds to reach the initial point and by this time B has moved 2740.08 units in the positive x direction, which then A takes 228 seconds to get to... and so on and so forth.

I've tried searching for similar problems but havent come up with anything although I would believe its a pretty common problem...

Help? Thanks