Four types of contact forces (also called mechanical forces):
compression, tension, torsion, shear
contact force that pushes things together
compression
contact force which pulls things apart
tension
contact force which twists objects
torsion
contact force which causes portions of a material to distort or move in opposite directions along parallel planes
shear
forces that are exerted between objects that are not touching
action-at-a-distance forces or field forces
Three types of field forces
gravitational field, magnetic field, and electric field
Gravitational acceleration near the earth's surface
9.81 m/s2
The gravitational force is directly proportional to the product of the masses and inversely proportional to the square of the distance between the masses
Law of Universal Gravitation
Formula for linear momentum
p=mv
Objects at rest remain at rest, and objects in motion continue in a straight line at a constant velocity unless acted upon by a net external force.
Newton's law of inertia (Newton's First Law of Motion)
The acceleration of a system is directly proportional to the net force acting on the system and is inversely proportional to its mass.
Newton's Second Law-The Law of Accelerated Motion; F=ma
For every external force exerted on a system by its surrounds, the system exerts an equal but opposite force on its surroundings
Newton's Third Law of Motion (action-reaction principle)
unit of force in the SI named in honor of the great English scientist