====== Forces ======
A force is an interaction that would change the motion of a given object. The diagram below shows the forces typical of an object in any given system.

{{:physics:img_0098.jpeg?400|}}

Where:
  * $F_n$ is the normal force
  * $F_r$ is friction
  * $F_a$ is the applied force
  * and $W$ being weight

===== Weight =====
Mass is the density of the object while weight is its resistance against gravity. Volume is related to mass via density. Weight is mass multiplied by gravity. $W = mg$

===== Applied Force =====
Applied force is the force exerted on an object in a system externally. Typically it's given to you. It can also be substituted with a force like tension.

===== Normal Force =====
The normal force is what is exerted when a object rests against another. Typically, this force is equivalent to the weight of the object(($F_n = W$)), unless it is a special situation like an [[physics:incline_plane|incline plane]]. In those cases, the normal force may be offset from the weight.

===== Friction =====
Friction is a force caused by the collision of surfaces that are inherently uneven. It is mathematically defined as $F_r = \mu F_n$ where $F_r$ is friction, $F_n$ is the normal force((opposing force of weight when object is resting on a surface)), and $\mu$ being the coefficient of friction(([[physics:newtons_laws_of_motion|Newton's second law]] is useful here if you want to find the friction coefficient given an acceleration without mass present)). The coefficient of friction is a uniform value((0-1 linear value)). There are two types of friction.

==== Static Friction ====
This type of friction prevents an object from sliding against another surface parallel to the contact area.

==== Kinetic Friction ====
This type of friction slows an object instead of preventing its movement. Direction is opposite to the object's net force.
===== Tension =====
See: [[physics:solving_tension_problems|Solving Tension Problems]], also [[physics:incline_plane|Solving Incline Plane Problems]] for Tension on an incline plane.

Tension is a force that a rope((/string/chain)) exerts pulling one object to another.

==== Finding Acceleration ====
The acceleration of tension can be calculated by summing the forces of each object under tension by the sum of their masses(($a = \frac{\sum F}{m}$ where $F$ are the forces and $m$ is the total mass of the objects)).

=== Force of Tension ===
FIXME No clue if this is right, disregard if you're doing something important

You can use [[physics:newtons_laws_of_motion|Newton's Second Law]] (($F_{net} = ma$)) to calculate the force of tension, with $F_{net}$ being the sum of all forces in the system ($\sum F$), $m$ being the mass of the two objects in tension, and $a$ being the value calculated before.

==== From Weight and Net Force ====
Tension can also be associated as equal to the net force of the system minus an acting force, typically weight $F_{net} = T - W$.