Transcript of Honors Physics Semester 1 Review PowerPoint. Distance vs Displacement 0 1 2 3 4 5 6 7 8 9 Distance =...
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- Honors Physics Semester 1 Review PowerPoint
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- Distance vs Displacement 0 1 2 3 4 5 6 7 8 9 Distance =
magnitude only = 8m Displacement = magnitude and direction = x = x
2 x 1 x = x 2 x 1 = 9m 1m = +8m
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- Acceleration When you increase your speed in a car, are you
accelerating? When you turn in a car, are you accelerating? When
you slow down in a car, are you accelerating? This is called
deceleration or negative acceleration or acceleration in the
direction opposite of the cars movement.
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- Objectives: define distance and calculate speed, and explain
what is meant by scalar quantity. Scalar Quantity: Quantity with
only a numerical value Distance tells us how far but not in what
direction. Time Mass Temperature
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- Graphical Analysis Zero accelerationPositive acceleration
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- Kinematics Speed: the rate at which distance is traveled
Constant Speed: speed of object does not change Average speed =
total distance/total time Units: meters m second s
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- REVIEW: Motion: change of position Scalar: numbers only Vector:
direction Velocity: change of speed in a given direction
Acceleration: a change in velocity Therefore, a change in speed or
a change in direction
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- Graphs Position v Time graphs constant velocity v =
acceleration
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- Speed and Velocity There are two types of Velocity: 1. Average
Velocity V = d/t For example, when a car moved 50 km in 2 hours,
the average velocity is 25km/h. 2. Instantaneous Velocity For
example, when the speed cameras give you a ticket, they show the
car driving at 90 km/h for that instant.
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- Velocity What is the velocity of this object between 0-4 sec?
What is the initial starting position of the object? What is the
displacement of this object from 3-4 seconds? What is the objects
final position? Position in Meters
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- Graphs Assuming the objects motion does not change, what would
its position be at t=20s? Time (seconds) Position in Meters
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- What is happening to the velocity of these two objects? What is
happening at t=2s? At t=4s, which object has greater speed?
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- Graphical Analysis Zero accelerationPositive acceleration
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- Newtons First Law of Motion or Law of Inertia: in the absence
of an unbalanced force, a body at rest remains at rest, and a body
in motion remains in motion with a constant velocity (speed and
direction).
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- Inertia and Newtons 1 st Law Inertia - tendency of an object to
overcome a change in motion Characteristics: more mass = more
inertia Mass is the quantitative measure of inertia.
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- Net Forces
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- Normal Force When an object is sitting on a level surface then
the normal force is always equal and opposite of the weight of the
object.
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- Forces Symbols F app applied force (push or pull) F g force of
gravity (always toward center of earth or down) F n normal force
(always perpendicular to surface) F f force of friction (same as
surface)
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- Balanced forces do not change the objects motion.
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- FORCES Unbalanced forces result in a change in the objects
motion.
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- Newtons First Law of Motion or Law of Inertia: in the absence
of an unbalanced force, a body at rest remains at rest, and a body
in motion remains in motion with a constant velocity (speed and
direction).
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- Newtons 3 rd Law of Motion For every force (action), there is
an equal and opposite force (reaction).
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- Free Fall Force of Gravity ONLY Free Fall: A Particular
Acceleration How fast a falling object moves is entirely DIFFERENT
from how far it moves. We will treat x and y separately
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- SI Unit: Newton = kg m/s 2 Force is a vector
(magnitude/direction) Like velocity and acceleration, force has a
strength AND a direction
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- FORCE Resultant Force: the total of all forces acting on an
object. Force 1 pushes upward with 2 N Force 2 pushes horizontally
with 5 N
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- Net Forces with angles
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- What is the net force on this object? What is F s ? What is F N
? Pull Force of 20 N at 16 50kg
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- Types of Friction Static Friction: Frictional force is
sufficient to prevent motion between surfaces.
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- Static Friction Formula f s s N (static conditions = no
movement) s coefficient of static friction
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- Friction (think about ice)
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- Normal Force Normal means perpendicular. Force that a surface
exerts on an object.
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- Normal Force When an object is sitting on a level surface then
the normal force is always equal and opposite of the weight of the
object.
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- Force Formula Acceleration of an object is directly
proportional to the net force and inversely proportional to its
mass. Acceleration = Force Mass
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- Momentum and Impulse The concept of impulse and momentum using
Newtons 2nd Law: F = ma a = v f v i = vF = m v t t t Take t to the
other side: Impulse-Momentum Theorum = F t = m v F(t) is called
IMPULSE. It is defined as a force acting through time. Impulse is
numerically equal to the of momentum. So a force acting for time on
some object gives rise to a change of the objects momentum.
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- Is momentum conserved? YES. The momentum lost by one object is
gained by the other object. The total amount is constant.
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- Elastic Collisions Total Kinetic Energy is conserved Follows
the Law of Conservation of Momentum K after = K before
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- Inelastic Collisions Kinetic energy is NOT conserved Change in
original shapes Sound and friction KE lost
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- Linear Momentum Formula: = m v = momentum m = mass v = velocity
SI Units? kg m/s
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- Law of Conservation of Linear Momentum: "the total momentum of
an isolated system of interacting bodies remains constant." OR
"Total momentum of an isolated system before collision is always
equal to total momentum after collision. Correlates to Newtons 1 st
Law of Motion
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- Radians Correct SI unit for angular measurements radius to arc
length = radian (The Rad) 1 rad = 360/2 = 57.3 Calculators: switch
to rad when told
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- Period and Frequency Frequency: number of cycles per unit of
time. f = 1/t or s -1 Period: (t) time it takes an object in
circular motion to complete one revolution or cycle t = 1/f
Frequency and period = inverse relationship Frequency SI: 1/s =
Hertz (Hz) Heinrich Rudolf Hertz
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- Uniform Circular Motion Needs 3 things 1. Centripetal
Force
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- Uniform Circular Motion 2. Angular Acceleration 3. Constant
Speed V= Tangential velocity wants to go in a straight line
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- Gravitational Field Lines for Two Objects
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- Keplers 3 rd Law of Planetary Motion This Law lets us determine
a newly discovered planets distance from the Sun.
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- Keplers Laws of Planetary Motion Keplers 2 nd Law: (Law of
Areas) A line from the Sun to a planet sweeps out equal areas in
equal lengths of time.
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- Escape Velocity What kind of energy must a man-made satellite
have to escape Earths gravitational pull? What kind of energy must
a man-made satellite have to escape Earths gravitational pull?
Formula for Escape Velocity: Formula for Escape Velocity: Escape
speed = escape surface of Earth is about 11km/s or 7mi/s
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- Centrifugal is just Inertia what Law? Newtons 1 st : an object
in motion wants to stay in that motion and not change speed or
direction unless acted upon by an outside force.