Minimize Distance

  • #1
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0

Homework Statement


Mike, who i standing on the deck of a yacth that is travelling due west at 6km/h, sees a sailboat sailing southwestat 4km/h, 3km northwest of the yacht. How close to each other do these boats get?


Homework Equations





The Attempt at a Solution


My drawing is:
| A(2.12-4t,2.12-4t)
| / \
| / \
|/__\B(4.24-6t,0)

Used pythagorean theorem to find t [tex]D^2=(2.12-4t-0)^2+(2.12-4t-(4.24-6t))^2[/tex]

Correct so far?
 
Last edited:

Answers and Replies

  • #2
HallsofIvy
Science Advisor
Homework Helper
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966
You have sailboat A with a velocity of <-4, -4>. That gives a speed of
[itex]\sqrt{16+ 16}= 4\sqrt{2}[/itex], not 4. You need to multiply by
[itex]\frac{\sqrt{2}}{2}[/itex], just like you did with the initial position.

And it would be a good idea to specifically state, in your final answer, which sailboat is A and which B and how your coordinate system is set up.
 

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