**Newtonian Mechanics** The velocity of a particle can change when one or more forces (pushes or pulls) act upon it.

**Force** Forces are vector quantities (see Chapter 3:Vectors) Their magnitudes are in terms of the accelaration they would supply to a mass weight in kilograms. a force that accelerates a 1 kg body by 1 m/s^{2} has a magnetude of 1 Newton. Newtons are the unit of measure for forces. A force's direction is the same as the acceleration is causes. The net force on a body is the vector sum of all forces acting on the body.

**Newton's First Law** A body at rest remains at rest unless acted upon by an unbalanced external force.

**Inertial Refrence Frames** Rafrence frames in which newtoniam mechanics hold are called inertial refrence frames or inertial frames. Frefrence frames in which newtonian mechanics do not hold are called noniinertial refrence frames.

**Mass** Mass is a caracteristic of a body that relates the body's acceleration and the net force on that body. Mass is a scalar quantities.

**Newton's Second Law** The net force (F_{net}) on a body with mass *m* is related to the bodys acceleration *a* by:

which can also be written in component form:

The Newton is the SI measurment for force:

A free body diagram is a diagram in which all the external forces on a single body are drawn on a coordinate system, oriented as to simplify the solution.

**Specific Forces** Gravitational force (F_{G}) on a body is a pull by another body. Usually, the second body is earth. The gravitational force is given by:

Where *m* is the particles mass, and *g* is the free fall acceleration. (the free fall acceleration on earch is 9.8 m/s^{2})

the weight (*W*) of a body is hte magnitude of upward force needed to balance the gravitatioinal force on a body. Weight is given by:

A normal force (F_{N}) is the force on a body from a surface on which it presses. A normal force is always perpendicular to the surface.

A frictional force is the force on a body when a body attempts to slide along a surface. the force is always opposed to the sliding and parallel to the surface.

when a cord is under tension, each end of the cord is pulling on a body. the pull is directed parallel to the cord. On a massless cord, the tension at both ends is equal even if it runs around a massless frictionless pulley.

**Newton's Third Law** The force of object B on object C is equal to the force of C on B. (For every action, there is an equal and opposite reaction.)

All information and equations are taken from and credited to Jearl Walker's Fundamental Physics.