What is the period of a wave that completes 3 waves in 2 seconds?

1.5

Explanation:

Period=no. Of waves/time

Period=3/2

=1.5

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west