Thread: Vector help

Hey guys I need some help on this question...

A spelunker is surveying a cave. She follows a passage 180m straight west, then 230m in a direction 45 degrees east of south, and then 280m at 30 degrees east of north. After a fourth unmeasured displacement, she finds herself back where she started.

1. Use a scale drawing to determine the magnitude of the fourth displacement. 2. Determine the direction of the fourth displacement. Two sig digs.

So where should I start I'm terrible at vectors.

Originally Posted by Oldspice1212

Hey guys I need some help on this question...

A spelunker is surveying a cave. She follows a passage 180m straight west, then 230m in a direction 45 degrees east of south, and then 280m at 30 degrees east of north. After a fourth unmeasured displacement, she finds herself back where she started.

1. Use a scale drawing to determine the magnitude of the fourth displacement. 2. Determine the direction of the fourth displacement. Two sig digs.

So where should I start I'm terrible at vectors.

acquire some graph paper and a protractor for the scale drawing ... sounds to me like this is a exercise in actual physical measuring using scale to come up with a solution.

Hello, Oldspice1212!

I hope you're familiar with the basics of vectors.

A spelunker is surveying a cave.
She follows a passage 180m straight west,
then 230m in a direction 45 degrees east of south,
and then 280m at 30 degrees east of north.
After a fourth unmeasured displacement, she finds herself back where she started.

1. Use a scale drawing to determine the magnitude of the fourth displacement.
What a clumsy way to get a measurement!

2. Determine the direction of the fourth displacement. (Two sig. digits)

Let North and East be positive.

Going from A to B: 180 m west.
. .

Going from B to C: 230 m, 45^o east of south.
. .

Going from C to D: 280 m, 30^o east of north.
. .

Add the vectors:
. .

Point D is 122.63 m east and 79.85 m north of point A.

Code:

                        * D
                     *  *
                  *   θ *
               *        * 79.85
            *           *
         *              *
    A *  *  *  *  *  *  *
            122.63

. . .

The direction of the last displacement is: 60^o west of south.


~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

By the way, the final magnitude is:

. . .

Thanks a ton so it would be 33 degrees south of west :P