I'm studying for an exam and this is one of the sample questions which I cannot figure out.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

Two ships A and B move with constants speeds 48 km/h and 60 km/h respectively. At a certain instant ship B is 30 km west of A and is travelling due south. Find:

i) The direction ship A should steer in order to get a close as possible to ship B.

2. Relevant equations

V_{ab}= V_{a}- V_{b}

3. The attempt at a solution

Well, V_{b}= 0i - 60j

V_{a}= -48cosxi - 48sinxj

and therefore

V_{ab}= -48cosxi + (60 - 48sinx)j

I have drawn diagrams to help but I can't figure out the right angle. I tried differentiation to find the lowest possible value for j (they are already horizontally across from each other) but I got 1 for an answer which I know is not correct. Any advice.

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# Homework Help: Relative Velocity question

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