AN AIRPLANE HEADS DUE NORTH 100MPH. IT EXPERIENCES A 20 MPH WIND FLOW IN THE DIRECTION S45(DEGREES)E. DETERMINE THE SPEED AND DIRECTION OF THE AIRPLANE.
Dreaded vectors. Draw your vector diagram and do each part individually then use the x and y components to get the final component for velocity (speed + direction)
To determine the speed and direction of the airplane, we can break down the velocities into their horizontal and vertical components.
1. Draw a vector diagram: Start by drawing a diagram with a northward arrow representing the airplane's velocity of 100 mph. Then draw a vector representing the wind's velocity of 20 mph to the southeast (S45°E). Label each vector accordingly.
2. Calculate horizontal and vertical components: To find the components, use trigonometry. The angle between the direction of motion (north) and the wind (southeast) is 45 degrees.
- For the airplane's velocity, the horizontal component (north-south) is 100 mph, as it is heading due north. The vertical component (east-west) is 0 mph, as the airplane is not moving in an east-west direction.
- For the wind's velocity, the horizontal component is 20 mph*cos(45°) = 14.14 mph to the east (positive direction). The vertical component is 20 mph*sin(45°) = 14.14 mph to the south (negative direction).
3. Combine components to find the resultant velocity: Add the horizontal components and vertical components separately:
- Horizontal component: 100 mph + 14.14 mph = 114.14 mph to the north
- Vertical component: 0 mph - 14.14 mph = -14.14 mph to the south
4. Calculate the magnitude and direction of the resultant velocity: To find the overall speed, use the Pythagorean theorem:
- Magnitude: √(114.14^2 + (-14.14)^2) = √(13000 + 200) = √13200 ≈ 114.93 mph (rounded to two decimal places)
- Direction: To find the direction, use trigonometry. The angle with respect to the north direction (x-axis) can be determined as follows:
θ = tan^(-1)((-14.14 mph) / (114.14 mph)) ≈ -7.03 degrees (rounded to two decimal places)
Since the resultant velocity vector points in the northern quadrant, adding 180 degrees to the negative angle gives the direction:
Direction: -7.03° + 180° = 172.97° (rounded to two decimal places)
Therefore, the speed of the airplane is approximately 114.93 mph, and its direction is approximately 172.97 degrees relative to the north.