Question

Please could someone explain this.

Answer 1

This problem is to let you practice using Newton's second law of motion:

Force = (mass) x (acceleration)

-- The airplane's mass when it takes off (before it burns any of its load of fuel) is 320,000 kg.

-- The force available is (240,000 N/per engine) x (4 engines) = 960,000 N.

-- Now you know ' F ' and ' mass '.  Use Newton's second law of motion to calculate the plane's acceleration.