Described by its strength and
direction in which it acts
Strength and direction can be represented by an arrow
which points in the direction of a force, and the length of the
are shows the strength of the force, the longer the stronger
Strength measured in the SI unit called
newton (N) named after Isaac Newton
Net force
The combination of all
forces acting on an object
Determines whether an object
moves and which direction it moves
Balanced forces
Equal forces acting on an object in
opposite directions, there is NO net force
No change in the
object's motion
Unbalanced forces
Whenever the forces on an object
are unbalanced, there is A net force
Change in the
object's motion
Friction
The force that two surfaces exert on each
other when they rub against each other
The strength of the force of
friction depends on two factors
How hard the surfaces push together
Types of surfaces involved
Four types of friction
Static Friction
Friction that acts on objects that are not moving
Sliding Friction
Two solid surfaces slide over each other
Rolling Friction
When an object rolls across a surface
Fluid Friction
When a solid object moves through a fluid
Gravity
A force that pulls objects
towards each other
The strength of the gravitational attraction
between objects depends on two factors
Mass
Measure of the amount
of matter in an object
Weight is the force of gravity on a person
or object on the surface of a planet
More mass greater gravitational pull
Distance
Less distance greater gravitational pull
Universal Gravitation
Law made by Newton that stated force of
gravity acts between all objects in the universe
Isaac Newton
Free Fall
When the only force acting on an object is
gravity, the object is said to be in free fall
In free fall the force of
gravity is unbalanced, which
causes an object to accelerate
All objects in free fall
accelerate at the same
rate regardless of masses
It does not seem like it because
all objects falling through air
experience air resistance
Air resistance is a fluid friction
Terminal Velocity
The greatest velocity a
falling object reaches
Projectile
An object object that is thrown is called a projectile
Isaac Newton
Newton had three laws of motion
The Second Law of Motion
The second law states that acceleration
depends on the object's mass and on
the net force acting on the object
Acceleration= Net Force/ Mass
The Third Law of Motion
The third law states that if one object exerts a force on
another object, then the second object exerts a force of
equal strength in the opposite direction on the first object
Basically meaning for ecery action
there is an equal but opposite reaction
Momentum
What Newton called "quantity of motion", it
is a characteristic of a moving object related
to the mass and velocity of the object
Momentum=Mass x Velocity
Law of conservation of momentum
The total momentum of any group of objects
remains the same, or is conserved, unless
outside forces act on the objects
The First Law of Motion
The first law states that an object at rest will remain at rest, and
an object moving at a constant velocity will continue moving at a
constant velocity, unless it is acted upon by an unbalanced force
This law is also called
the law of inertia
Inertia is the tendency of an
object to resist a change in motion