Warm-Up 8/31
• Pick up a Lab Safety Contract
• Contracts and Consumables Due Sep. 6th!
• UIL Science
Pre-AP Review
About Science
Chapter 1
About Science
• Units
Quantity
Displacement
Time
Velocity
Variable
x
t
v
Unit
m
s
m/s
Acceleration
Force
Momentum
a
F
ρ
m/s2
N
kg·m/s
Work
W
J
P
PE/KE
W
J
Power
Potential Energy/Kinetic Energy
Linear Motion
Chapter 2
Linear Motion
• Displacement vs. Distance
• Velocity
• v= x
t
• Acceleration
• a = Δv
t
Projectile Motion
Chapter 3
Projectile Motion
• Vectors
• Magnitude
• Direction
• Scalars
• Magnitude
Projectile Motion
vf = vi + at
vf2 = vi2 + 2ax
x = vit + ½ at2
• Use GUESS
• List what you know
• Pick your equation
• Remember “Important Points”
Projectile Motion
• Important Points
• Horizontal and vertical components
• Independent
• Vertical component
• Time
• Horizontal component
• Distance travelled
• Ball thrown vertically, velocity at the apex of its
trajectory?
• 0 m/s
Projectile Motion
• Vector Addition
• Pythagorean Theorem
• Resultant vector
• SOH CAH TOA
Newton’s Laws
Chapter 4, 5, 6
Newton’s Laws
• 1st Law
• A body at rest tends to stay at rest, a body in motion
tends to stay in motion unless a force is applied.
• 2nd Law
• F = ma
• 3rd Law
• For every action there is an equal but opposite
reaction.
• Action-Reaction Pairs
Newton’s Laws
• 1st Law
• A body at rest tends to stay at rest, a
body in motion tends to stay in motion.
• Except when there are external forces
• Inertia
• The tendency of the 1st Law
Newton’s Laws
• Newton’s 2nd Law
• F = ma
• Involved in all Newton’s Calculations
Newton’s Laws
• Newton’s 3rd Law
• For every action, there is an equal and
opposite reaction
• Action-Reaction Pairs
• You push on the table
• The table pushes back on you
• Baseball bat hits the ball
• The ball hits back
Newton’s Laws
• Net Force
• Overall Force on an object
• 0 net force
• All forces balanced
• Mechanical Equilibrium
• 0 acceleration
Momentum
Chapter 7
Momentum
• Momentum
• ρ = mv
• Impulse
• J = Δρ
• Δρ = ρf – ρi
• Δρ = mvf - mvi
• J = Ft
Momentum
• Conservation of Momentum
• Momentum before = momentum after
• Different equations for different
situations
Momentum
• Conservation of Momentum Equations
Situation
Equation
Objects collide
m1v1i + m2v2i = m1v1f + m2v2f
Objects attach
m1v1i + m2v2i = = mfvf
Objects separate (m1 + m2)vi = m1v1f + m2v2f
Momentum
• Collisions
• Elastic
• Momentum is conserved
• Inelastic
• Momentum is lost
• How?
• Sound
• Heat
• Damage
• etc.
Mechanical Energy
Mechanical Energy
• Work and Power
• Work
•W=Fx
• Power
•P= W
t
Mechanical Energy
• Mechanical Energy
• ME = KE + PE
• Potential Energy
• PE = -mgh
• Kinetic Energy
• KE = ½ mv2
Mechanical Energy
• Work-Energy Theorem
• W = ΔKE
• ΔKE = KEf – KEi
• ΔKE = ½ mvf2 – 1/2mvi2
Mechanical Energy
• Conservation of Mechanical Energy
MEi = MEf
KEi + PEi = KEf + PEf
½ mvi2 + -mghi = ½ mvf2 + -mghf
Thermodynamics
Change of Phase
• Going from one phase to another
• Occurs through the gain or loss of heat
Melting Vaporization Ionization
Solid
Liquid
Sublimation
Gas
Plasma
Change of Phase
Freezing Condensation
Solid
Liquid
Deposition
Gas
Deionization
Plasma
Universal
Gravitation
Gravity Equation
• Where
• F is force
• G is the universal gravitation constant
• m1 is mass of object 1
• m2 is mass of object 2
• d is distance between objects
32
Inverse Square Relationship
• Ratio of distances to force
Distance
1
2
3
4
1/2
Force
1
1/4
1/9
1/16
4
33
Relativity
Relativity
• Special relativity
• Space-Time
• Time dilation
• General relativity
• e = mc2
Electricity
Electrostatics
q1q2
F=k 2
d
Where
• F =Force
• k = proportionality constant
• q1 = charge of 1st particle
• q2 = charge of 2nd particle
• d = distance between charges
What’s the unit for q?
Ohm’s Law
I=V
R
• Where
• I is current
• V is voltage (potential)
• R is resistance
Units of Ohm’s Law
• Electric Potential, V
• Volts (V)
• Resistance, R
• Ohms (Ω)
• Current, I
• Amperes (A)
Electrical Power
P = IV
• Where
• P is power
• I is current
• V is voltage
• Unit for power
• Watt
Series Circuit
• Only one path for current to flow through
• All components have the same current
• Resistance in series
• Resistances add up
• RTotal = R1 + R2 + … + Rn
Parallel Circuits
• Multiple paths for electricity to take
• Voltage across each path is the same
• Resistance in parallel
• Inverse of resistances add up
• 1 = 1 + 1 + … + 1_
RTotal
R1 R2
Rn
Series vs. Parallel Summary
• A table comparing series and parallel circuits
• Voltage, current and resistance of each component
Circuit
Series
Voltage Current
Different Same
Parallel Same
Different
Resistance
RTotal = R1 + R2 +…
1 = 1 + 1 +…
RTotal R1 R2
Magnetism
Direction of a Magnetic Field
• When current flows down a wire…
• The “Right Hand Rule”
• With the right hand
• Stick your thumb in the direction of the current
• Your fingers show the direction of the field
Electromagnetic Induction
• A changing magnetic field and a wire causes…
• Current
• And Voltage
• Explained by Ohm’s Law
• I = V/R
• This is done by…
• Moving a magnet relative to a wire
Stepping Up and Down
PRIMARY
SECONDARY
• What type of transformers, step-up or stepdown, are they following? The primary coils are
on the left, the secondary coils are on the right.
Step-Up
Step-Up
Step-Down
Waves
Describing Waves
• Crest
• High point of a wave
Describing Waves
• Trough
• Low point of a wave
Describing Waves
• Wavelength (λ)
• Length of one wave (in meters)
• From Crest  Crest or Trough  Trough
Describing Waves
• Amplitude
• Height from the equilibrium (middle) point
• To either the crest or trough
Period and Frequency Equation
T = 1
f
• Where
• T is period
• Measured in sec
• f is frequency
• Measured in Hz
• Inverse of inverse seconds = seconds
Types of Waves
• Types of waves
• Transverse waves
• Longitudinal waves
• Standing waves
• Let’s look at each one…
Describing Transverse Waves
• Like we discussed before…
• Using crest, trough, wavelength, amplitude
Describing Longitudinal Waves
• Also called compression waves
• Compression
• Area of compressed media (increased density)
• Rarefaction
• Region of less media (decreased density)
Describing Standing Waves
• Nodes
• No motion
• Red dots
• Antinodes
• Maximum motion
• Crests and troughs
Interference Overview
In Phase
Constructive Interference
Out of Phase
Destructive
Doppler Effect
Stationary Object
Moving Object
• Notice the distortion of the sound waves in front
•
http://www.youtube.com/watch?v=imoxDcn2Sgo
Electromagnetic Spectrum
• Electromagnetic Spectrum
• All electromagnetic waves fall in this spectrum
Wavelength and Frequency
• Electromagnetic waves travel at the speed of light
• c = 3.0 x 108 m/s
c = λf
• c is constant, therefore:
• High wavelength
• Low frequency
• Low wavelength
• High frequency
AP Equation Sheet
• Used only on the free response
• Pick up copies
• 3 sheets