An airplane in flight has a pressure difference between the lower and upper wing surface; this provides an upward force that balances the weight of the plane.

If a plane has a wing area of 167 m 2 and a fully loaded mass of 77000 kg, what pressure difference is required to keep the plane aloft?

P_up-P_low = 4518 Pa

Explanation:

The pressure definition is

P = F / A

We cleared the force

F = P A

Let's write Newton's second law

∑ F = F_up - F_ low

∑F = P_ up A - P_low A

As the plane is in equilibrium (going at constant speed) the sum of force is equal to zero

A (P_up - P_low) - W = 0

P_up - P_low = W / A

P_up-P_low = 77000 9.8 / 167

P_up-P_low = 4518 Pa

assumptions that the area in the two parts of the wing is equal