Telle the whole process of how does bird is flying in sky

Hello Rohan!

A bird flies by fluttering or trembling its wings. Each flap is composed of one up stroke which produces no lift and one down stroke which produces lift. While the down stroke, the wing is much in a shape of flat sheet which maximises the drag on the wing as it pushes against the air, therefore producing lift. While the upstroke, the wing stops making lift as to stop the wing from forcing the bird towards the ground.

Bernoulli's principle states that fast-moving air applied less pressure than slow-moving air. Therefore, air instructed downwards results in the equal and opposite lift (Newton's third law). Also, each feather is like an airfoil, therfore as air flows through, there is an increase in lift and decrease in drag.

By repeating the cycle of upstroke and downstroke, the bird can experience a net upward force causing it to fly.

Hope this answer helps:)