Equations Flashcards

1
Q

Doppler Effect

A
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2
Q

Transverse waves

A

particle oscillation is perpendicular to the direction of propogation and energy transfer.

Example: light waves

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3
Q

Longitudional waves

A

particle oscillation is parallel to the direction of propogation and energy transfer

Example: sound

Think slinky

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4
Q

speed of wave

A

v = f lambda

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5
Q

Period of wave

A

T = 1/f

seconds per cycle

one cycle = one wavelength = 360 degrees

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6
Q

Intensity of sound

A

Intensity: power/energy per unit area

I = Power/Area

I is proportional to amplitude^2

I is proportional to 1/distance^2

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7
Q

Vector components

A

X = V cos angle

Y = V sin angle

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8
Q

Coulomb’s law

A

the electrostatic force between two charges

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9
Q

Electric field

A

Every electric charge sets up a surrounding electric field

E = F/q

E = kQ/r^2

F = the force between the charges

Q = charge that creates the field (source charge)

q = the charge placed in the field (test charge)

r = distance between them

*Coulomb’s divided by q (obviously b/c of first eqn)

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10
Q

Electric Potential Energy

A

The work necessary to move a charge in an electric field

U = kQq/r

q = charge that is being moved

Q = charge that is creating electric field (source charge)

*Coulomb’s times r

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11
Q

Electric Potential

A

electric potential = voltage

V = kQ/r

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12
Q

Kinetic energy

A

1/2 mv^2

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13
Q

Potential energy

A

U = mgh

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14
Q

Elastic Potential Energy

A

1/2 kx^2

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15
Q

Work

A

W = F d cos angle

W = (Change V) P

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16
Q

Work-energy

A

The net work done by forces acting on an object will result in a chnage in the KE

Wnet = K final - K initial

17
Q

Power

A

P = W/t = change Energy/ time

Watt = J/s

18
Q

Electrical Power

19
Q

Pressure

A

P = F/A

or F = AP

20
Q

Absolute (hydrostatic) Pressure

A

P = P(surface) + p (density) g z (depth of object)

P(surface) could be atmospheric pressure

21
Q

Hydraulic Systems

A

V = A1 d1 = A2 d2

W = F1 d1 = F2 d2

22
Q

Buoyancy Force

A

F = p(denisty fluid) V(fluid displaced) g

F = p(densiy fluid) V(submerged) g

If floating, F buoy = F gravity

23
Q

Flow rate

A

Flow rate is constant in a tube regardless of cross-sectional area

Q (flow rate) = A1 v1 = A2 v2

v = linear speed (which does change)

24
Q

Bernoulli’s eqn

25
density of water
1000 kg/m^3
26
Resistance
R = p(resistivity) L(length of resistor)/A (area) longer length = more resistance larger cross-sectional area = less resistance
27
Ohm's law
V = IR
28
Resistors in series
Rtot = R1 + R2 +... Current is same throughout each resistor Vtot = V1 + V2 +...
29
Resistors in parallel
1/Rtot = 1/R1 + 1/R2 +... Current splits at each branch in circuit I tot = I1 + I2 +... Voltage is the same through each resistor V tot = V1 = V2 =...
30
Sound level
B = 10 log(I/10^-12) I = intensity of sound wave (I = P/A) 10^-12 is threshold of hearing
31
String
antinodes = # harmonics = n lambda = 2L/n
32
Open Pipe
of nodes = harmonic # = n lambda = 2L/n
33
Closed pipe
#quarter-wavelengths (quarter circle) = harmonic # = n lambda = 4L/n
34
Electromagnetic spectrum increasing frequency
Radio Waves --\> microwave --\> IR --\> red --\> purple --\> UV --\> X rays --\> gamma rays
35
Energy of wave
E = hf = hc/lambda
36
Visible region
violet (400nm) --\> red (700nm)