FORCE
SYMBOL
DEFINITION
DIRECTION
Friction
Ff
The contact force that acts to oppose
sliding motion between surfaces
Parallel to surface and opposite
the direction of movement
Normal
FN
The contact force exerted by a surface
on an object
Perpendicular and away from
the surface
Spring
Fsp
A restoring force or the push or pull
exerted by a spring on an object
Opposite the displacement of
the spring
Tension
FT
The pull exerted by a string, rope, or
cable when attached to an object and
pulled taut
Away from the object and
parallel to the string, rope, or
cable at point of attachment
Applied
Fapp
A general term for the forces that move
objects.
Same direction as the
acceleration of the object
Gravity
Fg
The force that pulls all objects down
towards earth
Straight down towards earth
FN
Fg
Fg
Fair
Fg
FN
Ffric
Fapp
Fg
FN
Ffric
Fg
FN
Fapp
Fg
Fdrag
FN
Ffric
Fg