Classical_Mechanics

Classical Mechanics (often called Newtonian mechanics after Isaac Newton who made major fundamental contributions to the understanding of it) is the physics of objects moving in the ways we deal with every day. Examples in classical mechanics often involve things like hockey pucks on ice and balls being thrown through the air, because these things are relatively easy to make very accurate predictions about.

One of the fundamental concepts of classical mechanics is velocity.

v=d/t

where:

v is velocity

d is distance

t is time

The standard (SI) units for velocity are meters/second.

The SI unit for distance is meters.

The SI unit for time is the second.

Velocity is similar to speed, but velocity includes the direction of motion and implies that it must be in a straight line. This equation is used to calculate things like how far an object will go in a given time if it is traveling at a given velocity. Velocity is the derivative of distance with respect to time.

The next major concept is acceleration.

a=v/t

a is acceleration

v is velocity

t is time

The SI units for acceleration are meter/second^2 (pronounced meters per second squared).

Acceleration is the derivative of velocity with respect to time. The strength of a gravitational field is given in terms of acceleration. Since mass is not involved in this equation, that means that two objects dropped from the same height will land at the same time, assuming that air friction doesn't get in the way.

Acceleration can also be achieved by actually changing velocity. For example, if your acceleration is ten m/s^2, that means that every second you are going ten m/s faster than you were the second before. Slowing down (often called deceleration) is, in terms of physics, still called acceleration because you are still accelerating, just in the direction opposite of your motion.

The third big concept is force.

F=m*a

F is force

m is mass

a is acceleration

The SI unit for force is the Newton which is (kg*m)/(s*s)

The SI unit for mass is the kilogram (It isn't the gram mainly because the gram is smaller than most people can easily visualize)

Rockets in space are usually used as examples for this equation, because it isn't particularly intuitive here on earth with friction. Some specific rocket will produce a certain amount of force. If that rocket is pushing a small mass it will have a certain acceleration. If it is pushing ten times that small mass, it will have one tenth that acceleration.