The Four Concerned Forces

There are four main forces that act on a plane during flight and those are Drag, Lift, Thrust, and Weight. They are easily represented by this image.

This is actually somewhat true. Yes these forces are acting on the plane but there are also other such as gravity or wind from another direction. We can think of weight as being part of gravity in this case as lift has to overcome weight in order to gain lift. The four listed forces are actually the one we are concerned with in this case. Before we delve into those forces and the dynamics of a plane, lets simply discuss forces.

Force in a Nutshell

Force is found by Newton's Second Law F = M x A. From this equation, we can derive functions for forces such as gravitational forces, water, and other problems! Since force is actually a vector unit, forces can be described in different directions. This is useful because we may want to know what the forces are if two objects collided or what happens when an object with some velocity collides with an object that isn't moving, or even calculating the tension in a rope! A simple force problem would be:

F = M x A

M = 1 kg and A = g = -9.8 m/s^2

F = 1 kg x 9.8 m/s^2 = -9.8 N

Nothing impressive, but this equation is extremely useful when put into practice! Now we can begin to understand that force has a direction (which is a vector). Our calculation says that a 1 kg object is being affected by Earth's gravity at 9.8 m/s^2, thus the negative sign because it's falling in a negative direction based on a X and Y coordinate system.

Images From:

http://s.hswstatic.com/gif/airplane-forces2.gif

https://www.physics.uoguelph.ca/tutorials/vectors/19.gif