<h2>
Answer:442758.96N</h2>
Explanation:
This problem is solved using Bernoulli's equation.
Let
be the pressure at a point.
Let
be the density fluid at a point.
Let
be the velocity of fluid at a point.
Bernoulli's equation states that
for all points.
Lets apply the equation of a point just above the wing and to point just below the wing.
Let
be the pressure of a point just above the wing.
Let
be the pressure of a point just below the wing.
Since the aeroplane wing is flat,the heights of both the points are same.

So,
Force is given by the product of pressure difference and area.
Given that area is
.
So,lifting force is 
I believe the website www.asanet.org will help (:
I'm not sure if this is correct but it's what I'll do
This is free-fall problem.
Stone A is thrown upward, at the point it falls down to the place where it was thrown, the velocity is -15m/s.
Now I choose the bridge is the origin. From the bridge, stone A and B fall the same distance which means Ya = Yb ( vertical distance )
Ya = Vo(t + 2) + 1/2a(t+2)^2
= -15(t + 2) + 1/2(9.8)(t^2 + 4t + 4)
= -15t - 30 + 4.5(t^2 + 4t + 4)
= -15t - 30 + 4.5t^2 + 18t + 18
= 4.5t^2 +3t - 12
Yb = Vo(t) + 1/2a(t)^2
= 0 + 4.5t^2
4.5t^2 = 4.5t^2 +3t - 12
0 = 3t - 12
4 = t
Time for Stone B is 4s
Time for Stone A is 6s