text: please help with physics!!? the displacement vector for a 15.0 second interval of a jet airplane's flight is (2450, −2430) m. (a) what is the magnitude of the average velocity? (b) at what angle, measured from the positive x axis, did the airplane fly during this time interval? this is easy.  the displacement is sqrt(2450^2 + 2430^2) = 10 sqrt(245^2 + 243^2) = 3451 m, so the average velocity is 230 m/s.  (you had to divide by 15.)  for the angle, tan x = -243/245 = -0.99184  the angle is -44 degrees, 46 minutes