CASE STUDY CHALLENGE

Application of Derivatives: Traffic Speed Detection

The traffic police has installed an Over Speed Violation Detection (OSVD) system at various locations. These cameras can capture speeding vehicles from a distance.

Traffic Camera Radar Diagram

A camera is installed on a pole at a height of 5 m. It detects a car travelling away from the pole at a speed of 20 m/s. At any point, x m away from the base of the pole, the angle of elevation of the speed camera from the car C is θ.

On the basis of the above information, answer the following questions:

Answer the following:

(i) Express θ in terms of height of the camera installed on the pole and x. [1]
(ii) Find the value of dθ/dx. [1]
(iii)

(a) Find the rate of change of angle of elevation with respect to time at an instant when the car is 50 m away from the pole.

— OR —

(b) If the rate of change of angle of elevation with respect to time of another car at a distance of 50 m from the base of the pole is 3/101 rad/s, then find the speed of the car.

[2]