Two cars are driving towards an intersection from perpendicular directions.The first car's velocity is 10 meters per second and the second car's velocity is 6 meters per second.At a certain instant, the first car is 4 meters from the intersection and the second car is 3 meters from the intersection.What is the rate of change of the distance between the cars at that instant (in meters per second)?Choose 1 answer:(A) −11.6(B) −10.8(C) −5(D) −136
Q. Two cars are driving towards an intersection from perpendicular directions.The first car's velocity is 10 meters per second and the second car's velocity is 6 meters per second.At a certain instant, the first car is 4 meters from the intersection and the second car is 3 meters from the intersection.What is the rate of change of the distance between the cars at that instant (in meters per second)?Choose 1 answer:(A) −11.6(B) −10.8(C) −5(D) −136
Formulating Right Triangle: The distance between the cars can be represented by the hypotenuse of a right triangle, with the sides being the distances of the cars from the intersection.
Applying Pythagorean Theorem: Let's call the distance between the cars "d". Using the Pythagorean theorem, d2=42+32.
Calculating Distance: Calculating d, we get d2=16+9 which is d2=25.
Finding Rate of Change: Taking the square root of both sides, d=25, so d=5 meters.
Using Chain Rule: Now, we need to find the rate of change of d with respect to time, which is dtdd.
Differentiating Distances: Using the chain rule, dtdd=(dx1dd)(dtdx1)+(dx2dd)(dtdx2), where x1 and x2 are the distances of the cars from the intersection.
Determining Velocities: Differentiating d with respect to x1 and x2, we get rac{dd}{dx_1} = rac{4}{5} and rac{dd}{dx_2} = rac{3}{5}.
Calculating Rate of Change: The rates dtdx1 and dtdx2 are the velocities of the cars, which are −10m/s and −6m/s, respectively (negative because they are approaching the intersection).
Calculating Rate of Change: The rates dtdx1 and dtdx2 are the velocities of the cars, which are −10m/s and −6m/s, respectively (negative because they are approaching the intersection).Plugging in the values, dt2d2d=(54)(−10)+(53)(−6).
Calculating Rate of Change: The rates dtdx1 and dtdx2 are the velocities of the cars, which are −10m/s and −6m/s, respectively (negative because they are approaching the intersection).Plugging in the values, dtd2d=(54)(−10)+(53)(−6).Calculating dtd2d, we get dtd2d=−8−3.6 which is dtd2d=−11.6 meters per second.
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