Question

In an (x,y) co-ordinates system with x east and y north, an aircraft has the velocity components Vx = -170 ms-1 and Vy = 110 ms-1, and an acceleration of 6.4 ms-2 at an angle od 42 degree from the x axis. What is the angle of the velocity from the x=axis.
And what is the y-component of the acceleration?

Answer 1

angle of velocity: what is arc tan(y/x)?
arc tan (-170/110)=-57.09 degrees, or 57 deg W of N.

y component of acceleration: which way is the angle? up or down? ay=6.4sin(+-42); -42 if it is S of x