Military Flight Aptitude: A Brief Review of Physics
Physics questions can pop up on the Military Flight Aptitude Test. The term physics can intimidate a lot of students; physics is simply a course on the application of math and science to everyday life. Hearing that might put you more at ease. This article aims to review how to apply math and science to everyday problems.
Mass (and weight)
Mass and weight are two different animals. Mass is the amount of matter contained within an object, while weight is the force exerted by gravity on the object’s mass. This force acts on an object whether the object is falling, resting, or being elevated and results in a downward acceleration of 9.81 meters per second squared. The formula for calculating weight is
W = mg
where W is weight, m is the mass of an object, and g is the acceleration that results from gravity.
Motion in a plane (not in an airplane)
The preceding section gives you some conceptual ideas on motion; here you can look at how motion is applied. Motion can occur in one dimension, such as a car moving along a road or a ball thrown upward into the air. The big difference between these examples is the effect of gravity on the objects.
Kinematics equations involve five variables and can be used to mathematically solve for velocity and acceleration. (Kinematics is the study of the motion of a body.) If you know any three of the variables, you can easily find the rest. The five variables are
D = displacement
a = acceleration
Vi = initial velocity
Vf = final velocity
T = time
Given a constant acceleration, the equations that you use to find whichever variables you’re missing are
Vf = Vi + aT
D = Vi T + 1/2aT2
D = 1/2(Vi + Vf) @@ts T
Vf2 = Vi2 + 2aD
Force is any kind of input that causes an object to experience a change in direction, speed, or shape. Force has both magnitude and direction, which makes it a vector quantity. The formula for force (measured in newtons) is as follows:
F = ma
where F is the force, m is the mass, and a is the acceleration.
Force can be frictional, electromagnetic, or gravitational. Static frictional force is the force that opposes any movement of an object when the object is at rest, and kinetic frictional force is created by the opposing forces between the surfaces of objects that are in relative motion.
Gravitational force is the effect of gravity on an object. You don’t need to worry about electromagnetic force for the flight aptitude test. (Note: Other forces exist, but you don’t need those for the test either.)
Energy and work
Energy is defined as the potential to do work. The energy of an object can be divided into two types: potential and kinetic. Potential energy is the energy that an object has because of its position (for example, the bowling ball sitting in the upper shelf of your closet).
Kinetic energy is energy that results from motion. Both potential and kinetic energy change when work is done by or on an object. Work is the transfer of energy to an object when the object, because of the application of a force, moves. You can calculate the work done on an object by using the following formula:
W = F x d
where W is work in joules, F is the force in newtons, and d is the distance in meters.
The work you do against gravity is gravitational potential energy, and you can calculate it by using the following formula:
PE = mgh
where PE is the potential energy in joules, m is the mass, g is the acceleration because of gravity (9.8 meters/second squared), and h is the height above ground in meters.