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.

 

[tomcue]

As a scientist, it is important to approach problems with a critical and analytical mindset. In this case, it is important to first understand the concept of average force and how it is calculated.

Average force is the total force acting on an object divided by the total time interval in which the force is acting. In this problem, the total time interval is 7.3 seconds and the total force acting on the airplane is the force required to accelerate it from rest to its takeoff speed of 31m/s.

Using the equation F=ma, we can calculate the total force by multiplying the mass (1150kg) by the acceleration (31m/s^2). This gives us a total force of 35650N.

To calculate the average force, we divide this total force by the total time interval of 7.3 seconds. This gives us an average force of approximately 4883N, which is the same result you obtained.

It is important to note that this is the average force acting on the airplane during the entire 7.3 seconds. This average force is not the same as the force acting at any specific moment during the acceleration. It is possible that the force acting on the airplane may have been much higher at certain points during the acceleration, but the average force over the entire time interval remains the same.

In regards to your second example, it is important to check your calculations and make sure you are using the correct values for mass, acceleration, and time interval. If you are still getting a significantly different answer, it may be helpful to review the concept of average force and how it is calculated. I hope this helps clarify the concept for you.