FORCES
SP1d. Measure and calculate the magnitude of frictional
forces and Newton’s three Laws of Motion.
SP1h. Determine the conditions required to
maintain a body in a state of static equilibrium.

Anything that affects the motion of an
object
A PUSH or a PULL
Tension is a type of internal force when
strings, ropes, etc. are used to transmit
forces.
Forces
Force vectors are always drawn from
the point of application.
Always draw the vector pointing
away from this point.
Pushes are drawn as pulls from the
other side.
Forces are VECTORS
• Concurrent Forces – two or more
forces acting on the same point at the
same time.
• Resultant Force – a single force that
has the same effect as two or more
 Combining Force Vectors 
• A state of a body in which
there is no change in its
motion.
• At rest or constant velocity
• Must have no net (unbalanced)
forces acting on a body
Equilibrium
Equilibrant Force – a single force that
would produce equilibrium.
The equilibrant force is equal to and in
the opposite direction of the Resultant
force.
Equilibrant Force
To find the equilibrant force…
1) Find the resultant of the 2
concurrent forces
2) The equilibrant force must have the
same magnitude, but act in opposite
direction.
To Find…
• 2 components to 1 resultants
• Concurrent forces can be composed
• Finding the resultant
• 2C’s  1R
Composition of Forces
• 1 resultant to 2 components
• Finding the components when the
resultant is known.
• Resolving the resultant vector into its
component vectors
• 1 R  2 C’s
Resolution of Forces