Question

how to work of helicopter when its thrusts out on pickup purpose..

Answer 1

If you see the Bernoulli's equation then you find that velocity of air in a space is inversly propotional to the pressure..

so,
As in helicopter the wings come in motion they increase the velocity of air on that particular area.
and now if apply the Bernoulli's equation.
we find the Pressure will be decreases in that particular area..
so,
now a situation come that the pressure at lower area of helicopter is more and as compared to that wing's area..
so,
the air of lower portion exert preesure on the upper side..
this leads to raise up the helicopter.