# An ornithologist is in the field studying a formation of geese and is 180 m south, and 385 m west, of where she parked her car. Let u be the vector representing the distance between the...

An ornithologist is in the field studying a formation of geese and is 180 m south, and 385 m west, of where she parked her car.

Let * u* be the vector representing the distance between the ornithologist and her car, and let

*be the vector representing the straight line distance from the ornithologist to the formation.*

**v**If the lead goose flies over her car at an altitude 319 m

find |* v*|

find the angle btw * u *and

*using cos `theta` = u.v/|u||v|*

**v**Verify result using right angle trig.

*print*Print*list*Cite

### 1 Answer

An ornithologist is in the field studying the formation of geese. She is 180 m south, and 385 m west of where she parked her car. The lead goose flies over her car at an altitude of 319 m. `vec u ` represents the vector from the ornithologist to her car. `vec v ` represents the vector from the ornithologist to the lead goose.

Let the point where the ornithologist is standing be (0,0,0). The vector `vec u` is [180, 385, 0] and the vector `vec v` is [180, 385, 319]

The magnitude of `vec v` is `sqrt(180^2 + 385^2 + 319^2)` = 531.4

The magnitude of `vec u` is `sqrt(180^2 + 385^2)` = 425.

The angle `theta` between `vec u` and `vec v` is defined as `cos theta = (180^2 + 385^2 + 0)/(531.4*425)`

=> `theta = cos^-1(2125/2657)` = 36.89 degrees

Using the right triangle formed the angle is `tan^-1(319/425)` = 36.89 degrees

**The angle between the vectors is verified to be 36.89 degree.**