To find the displacement of the plane during the third leg (as a vector), multiply the velocity of the plane times the time that it travels at that velocity:
The velocity of the plane with respect to the ground v_PG is equal to the velocity of the plane with respect to the wind v_PW, plus the velocity of the wind with respect to the ground v_WG:
The direction of the wind is θ=280°, and its speed is 35mph:
The direction of the plane with respect to the wind is θ=70, and the magnitude of its velocity is the same as in the 2nd leg, which is 560mph. Then:
Add both velocities to find the velocity of the plane with respect to the ground:
Since 20 minutes is 1/3 of an hour, then the displacement during the third leg of the trip, is:
1st question:
To find the position of the plane from the origin, add the displacement vector to the position before the 3rd leg started, which is:
Then, the final position after the third leg, is:
Then, the final location of the plane, is:
2nd question:
To find how far from the take-off point the plane is, calculate the magnitude of the vector r:
Therefore, the plane is 828 miles away from the take-off point.
3rd question:
To find the direction of the plane (the angle θ), remember that:
Therefore, the direction of the plane is 39° from the East toward the North.