Equations

Question 1

Doppler Effect

Answer 1

Question 2

Transverse waves

Answer 2

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

Example: light waves

Question 3

Longitudional waves

Answer 3

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

Example: sound

Think slinky

Question 4

speed of wave

Answer 4

v = f lambda

Question 5

Period of wave

Answer 5

T = 1/f

seconds per cycle

one cycle = one wavelength = 360 degrees

Question 6

Intensity of sound

Answer 6

Intensity: power/energy per unit area

I = Power/Area

I is proportional to amplitude^2

I is proportional to 1/distance^2

Question 7

Vector components

Answer 7

X = V cos angle

Y = V sin angle

Question 8

Coulomb’s law

Answer 8

the electrostatic force between two charges

Question 9

Electric field

Answer 9

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)

Question 10

Electric Potential Energy

Answer 10

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

Question 11

Electric Potential

Answer 11

electric potential = voltage

V = kQ/r

Question 12

Kinetic energy

Answer 12

1/2 mv^2

Question 13

Potential energy

Answer 13

U = mgh

Question 14

Elastic Potential Energy

Answer 14

1/2 kx^2

Question 15

Work

Answer 15

W = F d cos angle

W = (Change V) P

Question 16

Work-energy

Answer 16

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

Wnet = K final - K initial

Question 17

Power

Answer 17

P = W/t = change Energy/ time

Watt = J/s

Question 18

Electrical Power

Answer 18

P =IV

Question 19

Pressure

Answer 19

P = F/A

or F = AP

Question 20

Absolute (hydrostatic) Pressure

Answer 20

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

P(surface) could be atmospheric pressure

Question 21

Hydraulic Systems

Answer 21

V = A1 d1 = A2 d2

W = F1 d1 = F2 d2

Question 22

Buoyancy Force

Answer 22

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

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

If floating, F buoy = F gravity

Question 23

Flow rate

Answer 23

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)

Question 24

Bernoulli’s eqn

Answer 24

Question 25

density of water

Answer 25

1000 kg/m^3

Question 26

Resistance

Answer 26

R = p(resistivity) L(length of resistor)/A (area)

longer length = more resistance

larger cross-sectional area = less resistance

Question 27

Ohm’s law

Answer 27

V = IR

Question 28

Resistors in series

Answer 28

Rtot = R1 + R2 +…

Current is same throughout each resistor

Vtot = V1 + V2 +…

Question 29

Resistors in parallel

Answer 29

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 =…

Question 30

Sound level

Answer 30

B = 10 log(I/10^-12)

I = intensity of sound wave (I = P/A)

10^-12 is threshold of hearing

Question 31

String

Answer 31

antinodes = # harmonics = n

lambda = 2L/n

Question 32

Open Pipe

Answer 32

of nodes = harmonic # = n

lambda = 2L/n

Question 33

Closed pipe

Answer 33

quarter-wavelengths (quarter circle) = harmonic # = n

lambda = 4L/n

Question 34

Electromagnetic spectrum increasing frequency

Answer 34

Radio Waves –> microwave –> IR –> red –> purple –> UV –> X rays –> gamma rays

Question 35

Energy of wave

Answer 35

E = hf = hc/lambda

Question 36

Visible region

Answer 36

violet (400nm) –> red (700nm)