ap review.notebook - massillon middle school review slides.pdfap review.notebook 1 april 24, 2015...
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AP Review.notebook
1
April 24, 2015
May 66:23 AM
AP Physics Review 2 D Motion
Kenimatic Equations for Constant Acceleration
The overall velocity of the projectile at any point of its motion is the vector sum of its x and y components at that point.
Problem Solving Strategy: 1. Sketch the path of the projectile, including initial and final position, velocities,
and accelerations. 2. Resolve the initial velocity into x and y components 3. Treat horizontal and vertical motion independently
~ Time is the only variable that can be used in both the x and y directions ~ a = 0 in the x direction unless otherwise stated. ~ a = g = 9.8 m/s2 = 10 m/s2 in the y direction.
vi(x & y) = 0 m/syi = y (height above ground)
y = 0 so Δy = 0 yi = yivf = y direction only
viy = viy vfy = viy
vtop = 0 m/s
viy = viy vfy = viy
vtop = vx
vix = vx vfx = vxOn the dished line, Δy = 0 m
On the ground, Δy = yi
Newton's Laws of Motion: 1. Law of Inertia = An object at rest stays at rest unless acted upon by an unbalanced force. An object in
constant straight line motion stays in that motion unless acted upon by an unbalanced force.
2. Relates Force, mass and acceleration by the equation: FNet = ma
3. Action / Reaction. Every force has an equal and opposite force.
Types of Forces: FNet = Sum of all forces = Σ F1 + F2 = ma Fg = mg = Force of Gravity = Weight
FT = T = Force Tension in a rope or string FN = Force Normal = Surface Push (Perpendicular)
Fs = Spring Force Fc = Centripital Force = Perpendicular to Velocity
v
vx = v cosθ
viy = v sinθ
θ
May 66:23 AM
AP Physics Review Forces
Combine to get Fc
Fc =mv2
r
Physics
Book
400
FN = F
FF ll
F ll
400
Fg
Problem Solving Strategy: 1. Sketch a free body diagram of the problem. Label all forces. 2. Resolve forces at angles into x and y components (unless inclined plane) 3. Treat horizontal and vertical forces independently
~ Clearly label +x and x, +y and y forces.
~ Sum all forces in the x direction. Same with y.
4. Balanced Forces means a = 0 and v = constant!!!
Incline Plane = Parallel and Perpendicular Components
= mg cosθ
= mg sinθmg
Friction can be up or down the incline plane opposite motion.
Pulley / Elevator Problems
3 kg
5 kg
To find a:ma = Fg5 Fg3
a sign match FBig
To find T: 1 Look at 1 Block
ma = Fg5 FT
ma = FT Fg3
On Elevatorma = FT Fg
a sign match direction
In Elevatorma = FN Fg
a sign match direction
Torque = F is perpendicularr is length between rotation and F
AP Physics Review Momentum
Impulse changes momentum
Problem Solving Strategy: Use for Collisions or Explosions 1. Sketch a diagram of the problem. Show before collision and after collision. 2. Resolve momentum's at angles into x and y components (independent)
3. Momentum in x is conserved. Momentum in y is conserved.
4. Elastic Collisions = Energy Conserved Inelastic Collision = Energy Lost
m1v1x
m1v1y
m1v'1x
m1v'1yp2 = p
x2 +
p y2
px = m1v1
py = 0
p'x = m1v1 = p1x + p2xm1
m2
m1
m2
p'y = 0 = p1y p2y
AP Physics Review Energy
Problem Solving Strategy: Do not use for Collisions or Explosions 1. Sketch a diagram of the problem. 2. Direction does not matter for energy.
U can convert directly to K.
3. Only time direction matters is when an object has an x velocity.
4. Set U and K equation to get the short cut equation.
5. W = Change in Energy. So W = U = K
vi = 0 m/s
Δh1v1 = √ 2 g Δh1
v1
v4
v3
v2
Δh4 = 0
Δh3
Δh2 = total hi v4 = √ 2 g Δh4 = 0
v3 = √ 2 g Δh3
v2 = √ 2 g Δh2
May 66:23 AM
AP Physics Review Other Equations in Newtonian Mechanics
Problem Solving Strategy: Things you should know...
1. P0 is pressure at the top of the fluid in interest. Usually air pressure 1 x 105.
2. h is depth in the fluid. 3. Buoyant Force on an object is equal to the weight of the displaced fluid. ρVg
~ Volume of displaced fluid = volume of object under water.
~ ρ = density of fluid V = volume of object submerged.
4. The Volume Flow Rate, FR = Av, has to be constant for a moving fluid.
5. Bernoulli's Equation, P + ρgy + ½ρv2 is a conservation of energy equation. ~ If fluid has no height, ρgy term = 0
~ If fluid area is so big v = 0 (Top of water tank), then ½ρv2 = 0
k = sp constantx = stretch / compress
ignore () sign
T = period = time for 1 cycle
Tspring depends on mass & k
Tpendulum depends on length & g
Lenght increases, T increases
G = gravitational constant
r = center of mass separation
Ignore the negative sign
L
Δh
vi = 0 m/s
Velocity at the Bottom = √ 2 g Δh
FT at Bottom = Fc = FT Fg
Time to Swing across and back. T
T = 2π √ L / g
Time to swing across. ½ T
Spring is at equilibrium position. F = 0 N.
Spring is at xmax. U is max.
K and v = 0
Spring is back at x = 0
U = 0 J K and v = max
Spring is at xmax. U is max.
K and v = 0
AP Physics Review Fluid MechanicsFor stationary
fluids
A v is Flow Rate. m3/s
P P0 = ΔP AKA Gauge Pressure
May 66:23 AM
AP Physics Review Thermal Mechanics
Problem Solving Strategy: Things you should know...
1. The ideal gas law is commonly used. They will give you PV graphs and ask for the temperature.
~ You can use this equation to solve for changes.
~ If you have number of molecules, use the kB equation.
2. Temperature comes from the motion of a substances molecules.
~ Motion is K... Kave is directly related to Temp!
3. U is internal energy, found by the KE of all molecules, or N Kave.
~ U = NKave = (3/2) N KB T = (3/2) n R T
~ It temperature increases, U increases.
4. Work is always work done "On the gas."
~ Contract = + W Expand = W
~ If pressure is not constant, than W = Area under the PV Curve
5. Q is the transfer of thermal energy, govern by the specific heat eq.
N0 = Avogadro's Number = 6.02 x 1023 particles/mole
n = = Number of Moles
N = Number of Molecules or Atoms
m
molar mass
PfVf nRTfPiVi nRTi
=
NN0
n =
Thermal Expansion
Rate of Heat Transfer
ΔU = (3/2) nRΔT
Not given but need!
ΔQ = mcΔTSpecific Heat
Only use if P is constant
Q Positive if energy is transferred into the system
Negative with energy is removed from the system
W Positive if work is done on the system
Negative if work is done by the system
ΔU Positive if the temperature increasesNegative if the temperature decreases
Thermal ProcessesIsobaric Pressure stays constant. This creates a horizontal line on a PV diagram. For an isobaric possess, W = PΔV
ΔU = Q + W or ΔU = Q PΔV
Adiabatic No heat is exchanged with the surroundings. This means that Q = 0. Understand that this does not mean that ΔT = 0
ΔU = 0 + W or ΔU = W
Isovolumetric
ΔU = Q + 0 or ΔU = Q
Isothermal Temperature stays constant. This means that there will be no change in internal energy. Any work done on the system is accompanied by a loss of thermal energy and visa versa.
0 = Q + W or Q = W
Isovolumetric Volume stays constant. This creates a vertical line on a PV diagram. Since you cannot take the integral (area under the curve) for a vertical line, W = 0.
ΔU = Q + W Understanding the Signs
The gas is being compressed, so work is done on the gas. This causes more collisions, increasing molecular motion, increasing temperature, increasing U.
Pressure is not constant, so you must find the area under the curve to calculate work. It is expanding so work is done by the gas ( W). The gases internal energy, U, must decrease.
The area inside the process A B C A is the net work done.
Because you start at A and end at A, PV is constant, so temperature returns to initial value. If ΔT = 0, then ΔU = 0.
May 66:23 AM
AP Physics Review ElectricityProblem Solving Strategy: Things you should know...
1. Like charges repel, opposites attack. 2. Electric Field lines show where (+) charges will go.
~ Point away from () charges and toward (+) charges. ~ E Field inside a conductor is 0 N/C. Must be at surface.
3. Electric Potential = V Potential (Stored) Energy = U
4. Forces are vectors, so you must think about x and y components. 5. Charge, q, is quantized. Comes in clumps of qe = 1.6 x 1019 C.
6. Voltage, V can be shown as ε in a circuit diagram. 7. Positive side of battery is the long plate. Current is always positive! 8. The voltage drop over any enclosed loop must be 0Ω.
~ Resistors and Capacitors in parallel have equal ΔV. 9. When hooked up in series, Capacitors have equal charge, q.
~ In series resistors have equal current, I.
10. VBat = Req Itot VBat Ceq = Qtot
11. Light bulb brightness is measured in Power (W). Increase P, increase brightness.
Only equation where the sign of the charge matters!
Potential Energy Stored in a Capacitor
R for a wire is equal to ρ, resistivity of wire,
length of wire, and Area
Combine to get P = I2R = V2/R
P also = W/t = E/t
Could be K = qV
or W = qEd
5 V 5 V 5 V 5 V
C1
+
C2
Series ConnectionEqual Charge or Current
Parallel ConnectionEqual Voltage Drop over all loops
12 V
2 Ω
4 Ω 5 μF4 μF
9 μF
12 V
2 Ω
4 Ω 12 V
2 Ω
4 Ω 5 μF4 μF
9 μF
When the switch first closes, the
capacitors are still uncharged. With
Q = 0F, V also must be 0, due to
C = Q/V. If the voltage over the
capacitor is 0, it acts like a wire.
If the switch is open, everything is uncharged.
C = Uncharged = Wire C = Charged = Unhooked
If the switch is open for a long time,
the capacitors are fully charged
(Steady state). The now receive all of
their possible voltage. Also, since they
are fully charged, no more charge or
current can flow through them and
they act as if they are unhooked.
RC Circuits
How to get Req.
Work your way down, then work back up solving for current (charge for capacitors) and voltage.
May 66:23 AM
AP Physics Review Magnetism 1. A Charge MOVING PERPENDICULAR through a magnetic field feels a force qvB acting on it.
~ The force felt is perpendicular to both velocty and BField~ Determined by Right hand Rule (Positive Particles / Current)
A B C
A segment of a currentcarrying wire in a magnetic field B. The magnetic force exerted on each charge making up the current is qv x B and the net force on the segment of length L is IL x B
F
v
B
(A) In this rule, the fingers point in the direction of v, with B coming out of your palm, so that you can curl your fingers in the direction of B. The direction of v x B, and the force on a positive charge, is the direction in which the thumb points.
(B) In this rule, the vector v is in the direction of your thumb and B in the direction of your fingers. The force FB on a positive charge is in the direction of your palm, as if you are pushing the particle with your hand.
BField In BField Out
Charges move in Circular Motion in a BField. Set FB = FC
+vi
X X X X X X X
X X X X X X X
Velocity Selectors combine E and B to allow charges with a specific velocity to pass through un deflected. FB = qvB, FE = qV, Set equal and solve for v.
qE = qvB so v = E/B
Velocity Selector
Second Right Hand Rule for a long Current Carrying Wire Two long parallel current carrying wires
can attract or repel each other. Each creates its own BField. Their created BFlield's can interact with the current in the other wire and exert a force on the other wire.
Third Right Hand Rule for a coil of wire acting like a Bar Magnet
Electromagnetic Induction
Pulling a wire through BField
creates induced ε (V) and I.
Electromagnetic Induction
Moving a magnet toward a coil of wire will induce a current that create a magnetic field that opposes the incoming / outgoing magnet.
F = qE
Used for induced voltage and current.
ε = V, so BLv = IR
AP Review.notebook
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May 66:23 AM
AP Physics Review Waves & Optics
n = λλn
Frequency does not change in n.
θIncidence θReflection
θRefraction
Amplitude
Rest Line
Govern by Snell's Law.
More Dense to Less Dense~ Toward the Normal
More Dense to Less Dense~ Away from the Normal
so
si
EyeEye Eye
I
O
Principle Axis Vertex
Center of Curvature
FocalPoint (f)
Principle Axis Vertex
Center of Curvature
FocalPoint (f)
FocalPoint (f)
Vertex(V)
FocalPoint (f)
FocalPoint (f)
Vertex(V)
FocalPoint (f)
Concave Mirror
Convex Mirror
Convex Lens
Concave Lens
Converging Devises
Images can be upright or inverted, enlarged or reduced, real or virtual
Diverging Devises
Images will be upright, reduced, and real.
+ + +
Total Internal Reflection
sisohihof
M
real
real
upright
upright
converging
upright
virtual
virtual
inverted
inverted
diverging
inverted
+ When When
M > 1 = Enlarged
M = 1 =
1 > M > 0 = Reduced
Mirror Directions:
1. In parallel, out through/away focus.
2. In through/toward focus, out parallel
3. In through / toward CofC, back through/ away from CofC
Lens Directions:
1. In parallel, out through/away focus.
2. In through/toward focus, out parallel
3. Straight through the vertex
Young's Double Slit Experiment
Proved light is a wave
L >>>>>> d
If that distance is nλ, then constructive interference
If it's ½nλ, then destructive interference
m = 1
m = 2
m = 0
m = 1
m = 2
1 Slit... Then d = slit width not slit separation.
This can happen with sound as well.
May 66:23 AM
AP Physics Review Atomic and Nuclear Physics
Kmax = qVs
E = hc
λ
For a Photon
Use for DeBrogli Wavelength questions. Can substitute mv
Stopping Potential / Voltage
Problem Solving Strategy: Things you should know...
1. Atomic Mass (energy) and Charge must be conserved. 2. Look for units and use the correct planks constant h. 3. Forms of atomic radiation (I did not cover...)
~ Alpha (α) Decay = Release 2P and 2N. Atomic mass 4.
~ Beta (β) Decay = N becomes a P and an e is released.
~ Fisson = split nuecleus (mass/energy and charge conserved).
~ Fusion = fuse nuclei (mass/energy and charge conserved).
4. Photon energy related to f. E = hf.
~ High f, low λ, high energy.
5. Electrons absorb (release) energy and jump up (fall down) an energy level with a difference of energy equal to the photon.
K = hf φKinetic Energy of ejected Electron
Energy of the photon
Work Function"Toll"
hfc = φ
E2 E1 = ΔE = hf
Cuttoff Frequency
Only works for light at the violent end of the spectrum. Violet light has a higher frequency so it has high energy. They love to ask in terms of wavelength.
Compton Scattering proves light (massless) has momentum.
E = hf = pc.
De Broglie took it further, said all matter moves in wave motion govern by λ = h/p = h / (mv)
n1 = Ground State
n2 = 1st Excited State (2nd E Level)
n3 = 2nd Excited State
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