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Force, Motion,
and Energy
Newton’s Laws
Speed, Velocity, Acceleration
Gravity
Motion
 Motion occurs when an
object changes its position.
 Three Types of Motion:
 Relative Motion
 You v. solar system
 Distance
 How far something moves
 Displacement
 Difference between the end and the start
 NOT total distance
Speed
 Distance traveled per unit of time
 Speed =
distance
time
 Example…
 You ran 2 km in 10 minutes.
What was your speed?
Velocity
Speed (a change in position over
a period of time), but in a specific
direction.
Example: The cars at the Texas
Motor Speedway drove a lap.
They go 120 mph for 60 sec W,120
mph for 30 sec S,120 mph for 60 sec
E, and 120 mph for 30 sec N. They
had a direction which means they
also had velocity.
Acceleration

Acceleration occurs when an
object changes its speed,
direction, or both.
Acceleration = change in velocity
change in time

When an object changes its
direction or speed, it is
accelerating.
Force
 A force is a push or a pull that
one object applies to another.
 A force can also cause an
object’s motion to change.
 EX) Sports
 Balanced forces are equal
in size and opposite in
direction.
Inertia
 Inertia is the tendency of an object to
resist any change in its motion.
 Objects with more mass have
more inertia.
Newton’s First Law
 An object in motion tends to
stay in motion and an
object at rest tends to stay
at rest until acted on by
an outside force.
Force, Mass, Acceleration
 For any object, the greater the
force, the greater the
acceleration.
 The acceleration of any object
depends on its mass AND the
force
exerted on that object.
 KEY CONCEPT: Force, mass,
and acceleration are
connected.
Newton’s
Motion
nd
2
Law of
 Describes how force, mass, and
acceleration are connected.
 REMEMBER:
 Net force = total forces acting
on an object.
 States that the net force acting on
an object causes the object to
accelerate in the direction of the
net force.
Newton’s
Motion
nd
2
Law of
 Acceleration of an object is determined by the
size of the net force acting on the object and
the mass of the object.
 So, the relationship between
acceleration, net force, and
mass can be defined as:
F = ma
Friction
 If we give a skateboard a push,
what happens?
 But according to Newton’s 1st
Law, what SHOULD happen?
 REMEMBER:
 When an object slows
down, its velocity changes; if its
velocity changes, it is accelerating.
If an object is accelerating, a net
force must be acting upon it.
Friction
 The force acting on the skateboard
is friction. Friction is the force that
opposes motion between 2
surfaces that are touching
each other.
 The amount of friction between
2 surfaces depends on 2 factors:
 The kinds of surfaces.
 The force pressing the surfaces
together.
Static Friction
 What does “static” mean?
 Applied force is equal to the friction
between the two surfaces.
Sliding Friction
 Applied force is greater than the friction
between the two surfaces.
Rolling Friction
 The friction between a rolling
object and the surface it rolls
on.
 Rolling friction is usually
much less than static or
sliding friction.
 That is why it is easier to pull
a load in a wagon rather than
dragging it along the ground.
Friction Foldable
Term
Friction
Static Friction
Sliding Friction
Rolling Friction
Definition/
Example
Picture
Newton’s Third Law
 For every action, there is an equal and
opposite reaction.
 Examples:
 Trampoline
 Rocket Propulsion