Posted by help on .
The force F = (3.2, 7.1) N acts on a mass of 1.15 kg. At time t = 0 s, the mass has a velocity v0 = (0.46, 0.36) m/s.
What is the angle (in degrees) of the initial velocity, measured counterclockwise from the +xaxis?
I got 38.04 degrees but isn't the right answer

physics 
drwls,
Since they are asking about initial conditions only, the force makes no difference
Vo,x = 0.46 m/s
Vo,y = 0.36 m/s
The Vo vector is aimed in the second quadrant, at an angle of arctan36/46 = 38 degrees to the x axis. That would be an angle of 142 degrees from the +x axis, measured counterclockwise.