Question

Can a human fly? and why?

Answer 1

Let us answer the following quesiton in two sub parts.

I am assuming here that you are asking the question whether humans can fly like birds by flapping the hands (equivalent to bird's wings). NO!, it is not possible for humans to fly by flapping. The shape of the wings of birds is what mainly allows them to fly. Everytime they flap, they generate lift because of the difference in pressure generated between the lower part of the wing and the upper part of the wing. Where as if you consider humans the shape of the hand doesn't enable us to create the difference in pressure needed for the same and hence it is useless to flap the hands.

Now, let us consider that we add some sort of an attachment to mimic the shape of the bird wing and you try to flap it. Sure it does generate some lift. But, the lift generated will not be enough to lift the human body because of the weight. This is exactly the reason why birds have bones that weigh very less reducing their overall weight. I hope it answers your question.