Answer:
D = 71.20 km
Explanation:
In this case, let's get the exercise by parts.
Part 1 would be the first displacement which is 30 km. However, it's displacing north to east 30°, so in this case, if we trace a line of this, it should be a diagonal. So we need to get the value of this displacement in the x and y axis.
Dx1 = 30 cos 30° = 25.98 km
Dy1 = 30 sin 30° = 15 km
Doing the same thing but in the second travel we have:
Dx2 = 70 cos 50° = 45 km
Dy2 = 70 sin 50° = 53.62 km
Now we need to know how was the displacement in both axis. In travel 2, the plane is moving north to west, so, in the x axis, is moving in the opposite direction, therefore:
Dx = -45 + 25.98 = -19.02 km
In the y axis, is moving upward so:
Dy = 53.62 + 15 = 68.62 km
Finally to get the resultant displacement:
D = √Dx² + Dy²
Replacing:
D = √(-19.02)² + (68.62)²
D = √5070.46
D = 71.20 km