A ship is first seen on a radar screen to be 9 km east of the radar site. Some time later, the ship is at 18km northwest. What is the displacement of the ship from the first location it is seen at?
25.2 km (INSERT ANGLE HERE?!?) degrees north of west
Northwest = 45o N. of W. = 135o CCW from +x-axis.
Disp. = 18km[135o] - 9.
Disp. = 18*Cos135-9 + 18*sin135 = -12.73-9 + 12.73i = -21.73 + 12.73i = 25.2km[-30.4o] = 25.2km[30.4o] N. of W.