Which three applications use technologies that apply the Doppler effect? A.
Air-traffic control
B.
Weather forecasting
C.
Building inspection
D.
Pest control

A, B & C are correct.

Explanation:

In physics, Doppler effect is a term used to describe the change in frequency of a wave during the relative motion existing between the source of the wave the person acting a the observer.

Looking at the options given, this Doppler effect is applicable to: air traffic control where traffic controllers attempt to direct the traffic on the ground; weather forecasting where the conditions of the atmosphere at a particular time and place is being predicted; and in building inspection where we can use a non destructive test equipment known as Schmidt hammer to career out min destructive tests on a building.

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me