Question

Precalc help vectors

Answer 1

Given: 15.6 mph South (-15.6)
7.1 mph West (-7.1)
We will use the negatives when we calculate the angle South and West are both in the negative direction

find the resultant vector using Pythagoras
15.6^2 + 7.1^2 = C^2
278.42 = c^2
c = 16.69 mph

now to find the angle
take the tan^-1 (-15.6/-7.1) = tan^-1 (2.197)
angle = 65.5 degrees
add to 180 since in 3rd quadrant
angle is 245.5 degrees

result is (16.69, 245.5)