What is the concept of average force and how is it calculated?

[jeansbeans]

Homework Statement

A 1150kg airplane starts from rest and accelerates forward for 7.3 seconds until it reaches its takeoff speed of 31m/s. What is the average force on the airplane during this time?

I tried F= ma, but I get a number that is far too large.
F= 1150kg times (31/7.3) = 4883.6N I tried on a similar problem with a similar weight and got an answer in the hundreds when the answer was simply 6N. Help please.

 

[rl.bhat]

Your answer is correct.