Zusammenfassung der Ressource
Physics
- Forces
- Frictional Force
- A force that Opposes
the movement of the
sufaces
- Static
Friction
- A force acted
on a stationary
object, this
friction must
be overcome in
order to have
movement
- Ff,s = µ*Fn
- Ff,s = Frictional Force
- µ= Coefficient of
Friction
- Fn= Normal Force
- The coefficients of
friction show how
easily one object can
slide against another.
- Kinetic
Friction
- The force that
acts against an
object that is
already in
motion.
- Ff,s = µ*Fn
- Ff,s = Frictional Force
- µ= Coefficient of
Friction
- Fn= Normal Force
- The coefficients of
friction show how easily
one object can slide
against another.
- Gravitational Force
- A force that attracts any
object with mass.
- Gravitational Force is always
directed down and constant
near Earth (or any other
planet).
- Fg = (9.8N/kg)*m
- Fg = Gravitational Force
- (9.8N/kg) = Ratio
between mass and
weight on Earth
- m= Mass
- Mass
- Amount of stuff, amount of "matter"
- Universal Quantity
- Measured with a Balance
- Units: Grams/Milligrams
- Weight
- Gravitational Force of an Object
- Location Dependent
- Measured with a Scale
- Units: Newtons
- This formula can change on another planet depending on
the acceleration due to gravity on the planet.
- Normal Force
- The normal force is the support
force exerted upon an object that
is in contact with another stable
object.
- Normal force can change, it
does not always equal to the
gravitational force. This often
occurs when the angle of force
application is different (because
this can affect the force
magnitude).
- Tensional Force
- A pulling force that is exerted
on each end of string, a cable, a
chain, etc.
- Spring Force
- The spring force is the
force exerted by a
compressed or stretched
spring upon any object that
is attached to it.
- Note: Springs are alwsys
analyzed with force on the
vertical axis
- There is a linear trend
between the FORCE A
SPRING EXERTS, and the
LENGTH THE SPRING
STRETCHES.
- The ratio (or slope)
between the spring force
and the spring's stretch
tells us if the spring is
stretched 1 m then the
force exerted increases by
a value of Newtons.
- Force needed to
compress or stretch
a spring from
equilibrium increases
linearly.
- Fs = K*ΔX + Fo
- Fs = Sping Force
- ΔX = Change in Position
- K = Spring Constant
- Fo = State of
Equilibrium
- This is also known as
Hooke's Law
- Laws of Motion
- Newton's First Law of
Motion
- "A body at rest remains at rest
and a body in motion continues to
move at a constant velocity
unless acted upon by an
unbalanced force. "
- In the absence of resistive
forces (friction, air resistance,
etc.), if an object has an
unbalanced force acted on it
then the speed and/or direction
changes.
- If an object has balanced
force acting on it then the
speed and direction is
maintained (remains
unchanged).
- Also known as the "Inertia Law"
- Newton's Second Law
of Motion
- "A force acting on a body gives it
an acceleration which is in the
direction of the force and has
magnitude inversely proportional
to the mass of the body:."
- FNet= m*a
- FNet = Net Force
- m = mass
- a = acceleration
- Relationship between net force
and acceleration
- If the resultant
force increases,
then acceleration
increases in the
condition that the
object stays the
same.
- Force directly affects acceleration
because unbalanced forces cause
acceleration.
- Newton's Third Law of
Motion
- "For every action there is an
equal but opposite reaction."
- Forces always come in pairs -
equal and opposite action-reaction
force pairs.
- Balanced Forces
- When a force PRODUCES a change in
motion
- Constant change in motion
- Resultant Force (Net Force) is NOT ZERO
- State of equlibrium
- Unbalanced Forces
- When a force DOES NOT PRODUCE a
change in motion.
- Constantly accelerating motion
- Resultant Force (Net Force) is ZERO
- Unbalanced = Object is Accelerating
- Kinematics and Motion
- Vectors
- A quantity that has
both magnitude and
direction.
- Example(s):: Velocity,
displacement &
acceleration
- Displacement
- A vector
quantity that
describes an
object's
change in
motion
relative to it's
starting
position.
- ΔX =
(1/2)*a*Δt^2
- ΔX = Change
in Position
- a =
acceleration
- Δt = Change in
Time
- Displacement can also be
determined by finding the
area under the curve of the
velocity-time graph.
- Velocity
- A vector
quantity that
describes the
rate at which
an object
changes its
position.
- V=Δx/Δt
- V = Velocity
- ΔX = Change in
Position
- Δt = Change in
Time
- Acceleration
- A vector
quantity that
describes the
rate at which
an object
changes its
velocity.
- A=Δv/Δt
- A =
Acceleration
- ΔV = Change in
Velocity
- Δt = Change in
Time
- Acceleration can be
determined by finding the
slope of the velocity time
graph which is exactly what
the equation: A=Δv/Δt does.
- Scalers
- A quantity that has
magnitude but NO
direction.
- Example(s): time &
speed
- Distance
- A scalar
quantity that
describes
how much an
object has
traveled.
- Speed
- A scalar
quantity that
describes how
fast an object
is moving.
- Constant Accelerated Particle Motion
- Speed Increasing in Positive Direction
- The slope of the position-time graph is increasing and positive; this
represents the velocity. The slope of the velocity-time graph is constant and
positive; this represents acceleration.
- Speed Increasing In Negative Direction
- The slope of the position-time graph is increasing and negative; this
represents the velocity. The slope of the velocity-time graph is constant and
negative; this represents acceleration.
- Speed Decreasing in NEgative Direction
- The slope of the position-time graph is decreasing and negative; this
represents the velocity. The slope of the velocity-time graph is constant and
positive; this represents acceleration.
- Speed decreasing in Positive Direction
- The slope of the position-time graph is decreasing and positive; this
represents the velocity. The slope of the velocity-time graph is constant and
negative; this represents acceleration.