May the FORCE be with you!!!
How is a Force Described?
How do balanced and
unbalanced forces affect an
object’s velocity?
What is a Force?
A force is described by its magnitude and by the directions in
which it acts.
Is force a vector???
“A force is a push or pull in a certain direction”
How do you measure Force?
The SI unit for force is the
NEWTON!!
For short, we just write (N).
Who was Sir Isaac Newton??
We use a SPRING SCALE to measure
Force.
When holding a Spring Scale vertically,
and something is hanging from it, is shows
the WEIGHT due to GRAVITY of an
object.
Net Force
The combination of all forces acting on a object is called
NET FORCE.
Example:
5N 5N 10N
-- + -- = -------
Two forces acting in the same direction produce a larger NET
FORCE than either original force.
Example:
5N -7N -2N
-- + --- =
Two opposite and unequal forces acting in opposite directions
produce a net force in the direction of the larger force.
Net Force Continued
Example:
10N -10N 0N
---- + ---- = 0N
Equal but opposite forces may cancel each
other out and produce no NET FORCE
Unbalanced Force
Unbalanced forces acting on an object will result in a
change in an object’s velocity.
Will the object be accelerating??
Ex: Pushing a box from one side, causing it to move across the
floor.
Ex: Two people pushing a box on opposite sides, BUT one
person is exerting a greater force. The box will slide across
the floor in the direction of the greater force.
Balanced Forces
Balanced forces acting in the OPPOSITE direction
will NOT result in a change in an object’s velocity.
Will the object be accelerating?
Ex: Tug-of-war between two equal forces and the rope does
not move