# The principles of kinematics on an airport runway.

How are the principles of kinematics used in determining the length of an airport runway?

Dale
Mentor
2020 Award
Hi rockysmommy, welcome to PF

The jet engines provide a certain amount of acceleration for the jet. Then you simply need to make sure that the runway is long enough to accelerate up to flight speed.

Kinematics is the study of motion based on measurements of position and time. Based on these measurements one defines velocity and acceleration.

Classical Mechanics applies Newton's laws of motion and other principles to predict motion of the plane, and Fluid dynamics is also necessary to fully characterize the problem of runway length.

The simple variables are the mass of the plane, the coefficient of lift generated by the wings, the coefficient of drag opposing forward motion through air, and the thrust provided to accelerate the plane along the runway.

A short take-off and landing (STOL) plane has low mass (light weight), makes plenty of thrust, has a relatively high lift coefficient, and relatively small drag coefficient.

Determining the minimum runway length requires the solution of a differential equation based on these inputs in the simplified model. Landing takes a shorter runway than take-off for a given plane in virtually all cases.

berkeman
Mentor
How are the principles of kinematics used in determining the length of an airport runway?

Can you list the kinematic equations of motion for us? And tell us a little about how you think they apply to your question?