Related Rates?
A road running north to south crosses a road going east to west at the point P. Car A is driving north along the first road, and an airplane is flying east above the second road. At a particular time the car is 15 kilometers to the north of P and traveling at 60 km/hr, while the airplane is flying at speed 190 km/hr 10 kilometers east of P at an altitude of 2 km. How fast is the distance between the car and the airplane changing?
A road running north to south crosses a road going east to west at the point P. Car A is driving north along the first road, and an airplane is flying east above the second road. At a particular time the car is 15 kilometers to the north of P and traveling at 60 km/hr, while the airplane is flying at speed 190 km/hr 10 kilometers east of P at an altitude of 2 km. How fast is the distance between the car and the airplane changing?
1 Answer
Explanation:
.
The picture below depicts the the locations of the Car and the Airplane.
Please note the purple arrow showing the direction of our view as we look at the right triangle
From the top picture, we can see that
Now, we can use the lower picture and calculate the distance
Let's plug the right hand side of equation 1 into equation 2 to substitute for
For simplicity, let's let:
Then our equation becomes:
We need to find the rate of change of distance
We know that, at the specified moment, the car is traveling at
The airplane is traveling at
The airplane is
Now, let's plug in known values at the specified moment:
At the specified moment, the distance between the car and the airplane is changing at the rate of