Question

Why must an air traffic controller know a plane's velocity

Answer 1

So they can avoid planes meeting up at the same time

Answer 2

1. In order to prevent collision

2. To be able to control free flow of air traffic

Step-by-step explanation:

The reason why it's paramount for air traffic controller to know the velocity of a plane is to enable them to avoid or prevent collision of planes coming in opposite direction. Knowing the velocity of the plane by the air controller would also give the air controller a good insight of how the air traffic should flow in oder to avoid accidents and disorderliness.