Lesson 15: Solving Vector Problems in 2 Dimensions
We can now start to solve problems involving vectors in 2 dimensions.
●
We will use all the ideas we've been building up as we've been studying vectors to be able to
solve these questions.
●
The majority of questions you will work on will involve two
noncollinear
(
not in a straight
line
) vectors that will become part of a rightangle triangle. If there are more that two vectors,
you will probably be able to use a trick or two that will allow you to get a triangle out of them.
Since the triangles will be rightangled, you will be able to use a bunch of your basic math skills.
●
Just use your regular trig (SOH CAH TOA) and Pythagoras (c
2
= a
2
+ b
2
).
●
Usually you'll want to be thinking about physics as you set up your diagram (so that you get
everything pointing headtotail and stuff) and then switch over to doing it like any math trig
problem.
Example 1
: On a hot summer day a person goes for a walk to see if they can find a 7 Eleven to buy a
Slurpee at. He first walks 3.5 km [N], then 4.2 km [E] , and finally 1.4 km [S] before getting to the 7
Eleven. Oh, thank heaven!
Determine
the displacement of the person.
A quick sketch will help us organize things so we can get to work.
This shows the vectors being added head to tail, and the
resultant that the person actually moved, start to finish.
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 Spring '09
 Knott
 Physics, Force, Euclidean vector, triangle, Vector Motors

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