Forces and equilibrium

Composition of Forces
Combining two or more forces into a single resultant force ®
Cases include:
Same direction → add forces
Opposite direction → subtract
Perpendicular → use Pythagoras
Angled → use cosine rule

Resolution of Forces
Splitting a force into components:
Horizontal
Vertical

Equilibrium of a Particle

Coplanar Forces
Forces acting in the same plane
Resolve into x and y directions to find resultant

Types of Forces
Weight (gravity) = mg
Tension (strings)
Normal reaction (surface force)
Friction (opposes motion)

Friction
Increases until limiting equilibrium
Depends on surface type

Inclined Plane Problems
Resolve weight into:
Parallel:
Perpendicular:

Applications
Tension in strings
Objects on slopes
Multi-force equilibrium problems