calculus

[yankeeh]

Guys can you help me about this?

A ship is sailing north at 22 km\hr. A second ship sailing east at 16 km\hr cross the path of the first ship 85 km ahead of it. How fast is the distance between them changing one hour later? When are they closest together?

 

[modus]

talk to me about it and i will help you. any ideas about how to start it? try to think of the ships in terms of the x-y plane. how are the two ships positioned relative to one another?

 

[HallsofIvy]

I recommend you set up a coordinate system with, say, the first ship at the origin. Its position at t= 0 is (0, 0). Since it moving north (up the y-axis) at 22 km/hr, what is its position at time t? What is the position, as (x, y), of the second ship at t= 0? Since it is moving east (parallel to the x-axis) at 16 km/hr, what is its position at time t? What is the distance between the two ships at time t?