1. Calculate the acceleration:

* The problem states the airplane accelerates at an average rate of 2.8 m/s².

2. Calculate the force:

* Use Newton's second law of motion: Force (F) = mass (m) * acceleration (a)

* F = (1120 kg) * (2.8 m/s²)

* F = 3136 N (Newtons)

Important Note: The length of the runway and the time of acceleration are not needed to calculate the force. These pieces of information might be used to determine the final velocity of the airplane or if the airplane can take off within the runway's length, but they are not directly relevant to calculating the force.