Adding forces

Force is reperesented in diagrams by a straight line with an arrow to show its direcion of action.

Usually more than one force acts on an object.

If an object is at rest, the forces must balance.

The [blank_start]resultant[blank_end] of forces acting in the [blank_start]same[blank_end] straight line is found by addition or [blank_start]subtraction[blank_end].

If two [blank_start]forces[blank_end] acting at a [blank_start]point[blank_end] are represented in [blank_start]size[blank_end] and [blank_start]direction[blank_end] by the sides of a [blank_start]parallelogram[blank_end] drawn from the point, their [blank_start]resultant[blank_end] is represented in size and direction by the [blank_start]diagonal[blank_end] of the parallelogram [blank_start]drawn[blank_end] from the point.

Scalars are added by ordinarny arithmetic, while vectors are added geomtrically.

The [blank_start]maximum[blank_end] value of friction is called starting or [blank_start]static[blank_end] friction.

When friction is [blank_start]less[blank_end] than its [blank_start]maximum[blank_end] value, it is called sliding or [blank_start]dynamic[blank_end] friction.