We have seen the planes moving in sky what decreases its speed? Its the Air resistance.
Air resistance is a force that is caused by air. The force acts in the opposite direction to an object moving through the air. Air resistance is the frictional force air exerts against a moving object. As an object moves, air resistance slows it down. The faster the object's motion, the greater the air resistance exerted against it. Air resistance affects all moving objects, from airplanes, rockets, and trains to car, bicycles, and even living things. Air resistance is the resistance against the air, which decreases the speed of the moving object. Its formula is given as,
c is air constant,
v is the object's velocity.