CBSE Class 9 Answered

Wind moving across the sail of a kite creates pressure. Lift results from this wind pressure being deflected along the face of the kite. In other words, the wind pushes up on the kite. Think of wind pressure like a hand, pushing the kite up into the sky and holding it there. If the hand is removed, the kite will fall.
At the same time, wind passing over the top of the kite creates an area of low pressure, like a vacuum, along the back of the kite. This creates a pull from behind.
DIHEDRAL:

The one other thing that is important in understanding flight is something called dihedral . This is a special word from geometry that describes the angle formed when two wings come together.

The dihedral angle of a kites wings helps the kite fly smoothly. If the wings lean back at the same angle, then the wind pushes equally on both wings. If one side of the kite begins to turn further into the wind, then the wind will push harder on that side until the kite becomes stable again. So with a proper dihedral angle built into the kite's design, it will fly properly balanced in the sky. We call that equilibrium . kite is shaped so that air will be slowed down if it is travelling under the lower surface of a kite and will speed up if it is travelling over the upper surface of the kite.