Question

A jumbo jet airplane has a mass of about 400,000 kg when fully loaded with over
400 passengers and takes off at a speed of 250 km/h. Determine;The takeoff speed when the airplane has 100 empty seats. Assume each passenger with luggage is 140 kg and the wing and flap settings are
maintained the same.

Answer 1

Lift == k v^2

Lift at 250 km/h = 400,000 g

100 * 140 = 14,000 kg
so lift needed = (400,000 -14,000) g Newtons
= 386 g Newtons

250^2/400,000 g = v^2 / 386,000 g

v^2 = 250^2 (386/400)
v = 250 sqrt (.965)
v = 245.6 km/h

Answer 2

A 40 tonne jumbo jet accelerates down the runway at 5 m/s^2. What must be the thrust on each of its four engines? What is the horizontal force that a 700 N pilot exerts on his seat?