Physics + Math Flashcards
What are 5 criteria for the FINER method?
- feasible
- interesting
- novel
- ethical
- relevant
What is the one difference between a positive and negative control?
Positive ensure change in dependent variable and negative ensure no change in dependent variable
What the three types of bias? Define
- Selection Bias: sample differs from the population
- Detection bias: educated professionals using their knowledge in an inconsistent way and search for an outcome disproportionately in cartain populations
- Hawthorne effect: changes in behavior of subjects when they are being observed
What are the 4 core ethical tenets in medicine?
- Beneficence: obligation to act in patient’s best interest
- Nonmaleficence: obligation to avoid treatments or interventions where the harm outweighs the potential benefits
- Autonomy: responsibility to respect patients; decisions and choices about their own healthcare
- Justice: responsibility to treat similar patients with similar care and distribute healthcare fairly
What are the three tenets of the Belmont Report?
- Respect for Persons: honesty between the subject and the researcher (informed consent)
- Justice: dictates which study questions are worth pursuing and which subjects to use (Morally relevant difference such as age)
- Beneficence: do the most good with the lead harm. Can’t perform an intervention without equipoise (treat both treatment as equal/not one superior)
What is the difference between statistics and parameters?
Sample data=statistics
Population data=parameters
What is the difference between internal and external validity?
External: refers to the ability to generalize study to population
Internal: the identification of causality between two variables in a study
What is the difference between accuracy (validity) and precision (reliability)?
- validity: ability of an instrument to measure a true value.
- reliability: ability of an instrument to read consistently
What does alpha mean in statistical tests? What does it mean for a p-value to be greater than alpha?
- alpha is the level of risk that we are willing to accept for incorrectly rejecting the null hypothesis
- we fail to reject the null hypothesis
What is the difference betwen type II and type I error?
Type II error occurs when incorrectly fail to reject the null hypothesis (liklihood that we report no difference between two populations when there is one)
Type I error: liklihood that we report a difference when there is no actual difference
What is the difference between power and confidence?
Confidence is the probability of correctly failing to reject the null
Power is the probability of correctly rejecting the false null (1-beta)
What happens to the confidence interval if the confidence level increase
increases
What does a low power mean?
it is more difficult to get results that are statiscally significant
What is three difference between static and kinetic friction?
- Static friction is between stationary objects and surface when at rest and kinetic friction exists between a sliding object and surface
- coefficient of static friction is always larger than the coefficent of kinetic friction
- static friction can take on many values depending on the mag of applied force, kinetic friction is a constant value
What are Newton’s three laws?
- Inertia: body at rest stay at rest, body in motion stays in motion. No acceleration no net force. no force–> no acel/constant vel
- F=ma
- every action has an opposite and equal rxm
Equation for toque?
torque =rFsin(theta)
What is the universal gravitation equation?
Fg=(Gm1m2)/(r^2)
What is elastic potential energy? What is the equation?
When a spring is stretvhed or compressed from its equilibrium length
U=(1/2)kx2
What are two examples of conservative forces?
gravitational and electrostatic
What is the equation for Work?
W=Fdcos(theta)
What is the difference between an isovolumetic (isochoric) process and a isobaric process?
Both involve a piston (W=P(deltaV))
isovolumetic (isochoric) process–> volume is constant/no work
isobaric process–> pressure kept constant
How do you find mechanical energy? What is one key idea of mechanical energy?
- Delta E: Delta K + Delta U
- it is conserved at all points of process
(ex: will return to the same height when on a trampoline)
What does the zeroth law of thermodynamics state?
objects that are in contact and that are in thermal equilibrium (no net exchange of heat) if they are at the same temp
What is the first law of thermodynamics?
- deltaU=q-w
What is the second law of thermodynamics?
objects in thermal contact and not in thermal equilibrium will exchange heat energy
What are the three differences between conduction, convection, and radiation?
- conduction: direct transfer of energy from molecule to molecule through collisions
- Convection: transfer of heat by physical motion of fluid over a material (only with liquids and gases)
- Radiation: transfer of energy by electromagnetic waves (can be done in vacuum)
What is the specific heat equation? What is the specific heat of water?
- q=mc(delta T)
- 4.184(J/gk) or 1 cal/gK
What is the phase change called from solid to gas? gas to solid?
solid to gas: sublimation
gas to solid: deposition
What are 4 special types of thermodynamic systems?
- Isothermal: no temp change (delta U=0)/q=w
- Adiabatic: no heat is exchanges/ q=0
- isobaric: pressure is constant
- isovolumetric: volume is constant/ W=0
How can you calculate entropy?
Delta S=qrev/T
What is the density of water?
1g/cm^3 or 1000kg/m^3
How do you find guage pressure?
P-Patm
What are 3 units for pressure?
1atm=760mmHG=1x10^5 Pa
What is the main idea of Pascal’s Principle?
For fluids that are incompressible, a change in pressure will be transmitted undiminshed to every protion of the fluid and to the walls of the container vessel
What are three important equations from Pasccal’s Principle?
- F2=F1(A2/A1)
- d2=d1(A1/A2)
- W=F1/A1(A1d1)
How do you find bouyant force?
Fbouy=pfgVsub
What is the equation for Poiseuille’s law?
- Q=(πr^4(deltaP))/8nL
n=viscosity of lique
Q=flow rate
L=length of pipe
What is turbulent flow?
It is rought and disorderly and causes the formation of eddies, swirls of fluid of varying sizes downstream of obstacle
What is the Bernoulli’s equation? Example?
- P1+(1/2)pv1^2 + pgh1=P2+(1/2)pv2^2 +pgh2
h=average height above a certain point/datum
(1/2)pv1^2 –> dynamic pressure: pressure associated with the movement of fluid
Ex: Venturi flow meter: cross sectional area decreases, linear speed must increases. As dynamic pressure increases, abosulte pressure must decrease so the fluid is lower in tube 2. Direct relatioship between cross sectional area and the pressure exerted on the walls of the tube. Venturi effect: at equal heights, speed and pressure of a fluid are inversly related
During exhalation, how does total resistance of encounter airways change as air leaves?
Total resistance increases because fewer airways in parallel
What happens to total resistance as blood flows from heart?
decreases because more vessels in parallel
How can you find tension in a chain that suspends something in water?
T=Fg-Fbuoy
What is the equation for Coulomb’s Law?
Fe=(kq1q2)/r2
How can you find the mag of the electric field?
E=Fe/q=kQ/r2
q= test charge (charge places in electric field)
Q=charge that creates the electric field
How do you find electric potential energy?
U=(KQq)/r
How can you calculate the electric potential?
V=U/q=(kQ)/r
How can you calculate voltage?
DeltaV=Vb-Va=Wabq
Wab=work needed to move a test charge q through an electric field from point a to point b
Where will charges move?
move to minimize potential energy and this depends on the sign of source and test charge
- Positive test charges will move from high potential to low potential
- negaitve test charges will move from low potential to high potential
What is an equipotential line?
a line on which the potential at every point is the same. The potential difference between any two points on an equipotential line is zero, so no work is done to move a test charge from one point on equipotential line to another point on line.
-equipotential lines are always perpendicualr to electric field lines
What are two facts about Ferromagnetic materials?
- Ferromagnetic has unparied electrons
- Ferromagnetc material will become strongly magnetized when exposed to a magnetic field)
What is Lorentz force?
charges have both electrostatic and magnetic forces(mag field exert force on moving charges) acting on them at the same time (sum of these)
What is the equation for magnetic force? What is the right hand rule?
FB=qvsin(theta)
theta=angle between the velocity v and the mag field vector B
(if the charge is moving parallel or antiparallel to the mag field vector, it will not experience a magnetic force)
To determine the direction of magnetic force: right thumb in direction of v and put fingures in direct of mag field lines. Palm will point in dir of force vector for a + charge
How do you calculate the force on a current carrying wire? What right hand rule do you use?
FB=ILBsin(theta)
L=length of wire
theta=angle between L and B
Thumb is direction of L and B is where you point fingures, FB is in direction of palm
What is the difference between electric field, mag field, and mag force?
Need charge for electric field, need moving charge to have mag field, need an external electric field acting on moving charge in any direction except parallel or antiparallel to external field to have mag force
Which way to mag field lines point with south and north?
point from north to south
What are the units for amps, voltage?
Amps (C/s)
Voltage (J/C)
What are the units for conducivity?
siemens(S)
What four physical quantities determine the resistance of a resistor?
- resistivity
- length: longer length, increase resistance
- cross sectional area: cross sectional area increases, resistance decreases
- temp: higher temp, greater resistance
R=(pL)/A
What is the equation for Ohm’s Law?
V=IR
What are three ways to find power in terms of V or I?
P=IV=I2R=V2/R
What are units for capacitance?
Farad=C/V
What is a dielectric material and what happens if you put it in between plates of a capacitor?
- it is a form of insulation
- put it inbetween plates it will increase capacitance by a factor called the dielectric constant (C’=kC)
C’=capacitance with diaelectric material present
How do you find the electric field in capacitor?
E=V/d
How do you find the potential energy of a capacitor?
U=1/2QV
What is the difference between kirchoff’s junction rule and kirchoff’s loop rule?
kirchoff’s junction rule: at any point or junction in circuit, the sum of current directed into that points equals the sum of current direct away from that points
Iin=Iout
kirchoff’s loop rule: around any closed circuit loop, the sum of voltage sources will always be equal to the sum of voltage drops. consequences of conservation of energy. The potential difference around a closed loop is 0
Vsource=Vdrop
What does a Ohmmeter measure and where should you place it in a loop?
- Resistance
- two points in series with circuit element of interest (have to have 0 resitance)
What are the 3 difference btw an ammeter and a voltmeter?
- ammeter measures current and a voltmeter measure voltage
- Ammeter needs to be in series with points of interest and voltmeter needs to be in parallel
- resistance of ammeter needs to be 0 and resistance of voltmeter needs to be infinity
What happens to the electric field between two plates of a capacitor if you add a resistor in series vs parallel?
- in series, will increase the resistance and decrease the voltage applied, decrease electricle field?
- adding one in parallel will not change the voltage drop and would not change the electric field
What is the difference between trasnverse and longitudinal waves?
Transverse: have oscillations of wave particles perpendicular to the direction of propogation
longitudinal: have oscillations of wave particle parallel to direction of propogation
What is damping of a wave?
decrease in amp caused by applied or nonconservative forces
What is the difference between infrasonic and ultrasonic waves?
Infrasonic: freq below 20Hz
ultrasonic: freq above 20,000 Hz
How do you calculate intensity of sound
I=P/A
What is beat freq? How do you calculate it?
fbeat=|f1-f2|
2 freq close in pitch and find resultant beat freq
What is the first overtone in an open and closed wave?
Open–> 2nd harmonic
Closed–> third harmonic
How do you find sound level and change in sould level?
Sound Level: B=10log(I/I0)
Change:Bf=Bi+ 10log(If/Ii)
What does the law of reflection state?
incident angle will equal the angle of reflection
Are EM waves transverse or longitudinal?
transverse with oscillating electric and mag fields
What are plane mirrors?
cause niether convergence nor divergence of reflected rays. Create virtual upright images. Images are always the same size as object.
What is total internal reflection? When does it happen?
- when light moves from a medium with a high index of refraction to a medium with a lower index of refraction
- total internal reflection incident angle must be large
90 degress for angle two to find incident angle
What is the lensmaker’s equation?
1/f=(n-1)(1/r1-1/r2)
What is the power of a lense?
- P=1/f
f has to be in m
What is myopia and hyperopia?
myopia: divergence of light to correct of nearsigntedness
hyperopia: convergence of light to correct for farsightedness
How do you find the power and magnification of a multiple lenses system?
1/f=1/f1+1/f2+…1/fn
P=P1+P2+…Pn
m=m1xm2x…mn
How do you find the position of dark frindge (min) in a double slit exp?
dsin(theta)=(n+1/2)wavelength
How does difraction pattern for a single slit differ from a slit with a thin lens?
diffraction through a single slit does not creat characteristic fringes when projected on screen. When lens is introduced, the additional refraction of light causes constructive and destructive interferene, creating fringes.
What is plane polarized light?
is light in which electric fields of all waves are oriented in the same direction
(opticallty active compounds with chiral centers producted plane polarized light). polarizing light only limits the electric field’s oscillation to only two dimensions
How does polarized filter impact the wavelegnth of light passing through filter?
plane polarization had no effect on wavelegnth but polarization does affect the amount of light passing through a medium and light intensity. polarized will only allow light through that is parallel to axis of polarizer
How do you find the max KE of an ejected electron?
Kmax=hf-W
W is the min energy required to eject an electrons (W=hfT)
any addition energy is converted into KE
What does mass defect state?
- actual mass of nucleus is less than sum of nuetrons and photons/unbonded nucleons have more energy and more mass than bonded constituents
- E=mc2
difference in calculated mass and actual mass is the mass that was converted into binding energy
What are the four fundamental forces?
- strong nuclear force
- weak nuclear force
- gravitation
- electrostatic force
What are the units of volts?
J/C
What is the tension in a rope if people are pulling at either end with 100N?
the tension will adopt the force value applied (100N)
What is the angle in the torque equation?
angle btw tension vector and radius vector
What is the different btw GHz and MHz?
GHz=10^9
MHz=10^6
What is the difference between ultrasound and ultraviolet waves?
ultrasound are longitudinal waves and ultraviolet waves of transverse waves
Does sound move slower or quicker through stiffer mediums?
faster
How does the decible scale work?
Ever 10 increase in dB, is a magnitude of 10 increase in intensity
What is the equation for doppler effect?
f’=f(Vsound+/-Vobserver)/(Vsound-/+Vsource)
3.75N
The horizontal components are equal so Rope 2 has a tension of 26
What is the equation for force on charge?
F=k(Qq)/r2
How can you find the strength of electric field using charge-to-mass ratio?
F=ma
F=Eq
ma=Eq
E=ma/q
q/m is charge to mass ratio
What keeps a charge stationary in electric field?
Eq=mg
How can you convert J to Latm?
101=1Latm
Latm is another unit for work and can plug into W=P(deltaV) equation to find change in V
Do convex mirrors always from virtual images?
Yes
How do you find the power of a lense?
P=(1/f)
make sure focal length is correct sign
Under what conditions does a convex lense produce a virtual image?
Convex lens are converging, when o>f, produce a real, inverted image
What is the equation for force by electric field?
F=qvBsin(theta)
What are two equations for electric field and what are two units for electric field?
Fe/q=kQ/r2
(N/c) or (V/m)
What are three equations to find electric potential? what is the unit for electric potential energy?
q(delta V)=Edq=(kQq)/r
J
What is the one equation for electric potential? what are the units?
U/q
J/C
What are the two equations to find voltage? What are the units?
W/q=(kQ)/r
J/C
What is Lenz’s Law?
change in mag field will always generate a current
What is the difference in V and I when charging a connected battery vs and discconected battery?
- connected: V is constant
- disconnected: Q is constant
What happens if the horizontal force is smaller than the amount to overcome static friction?
the static friction force will be equal in mag to the applied force
How do you find force of horizontal spring?
F=-kx
What is the Force of a vertical spring equal to?
Fs=Fg
What are other units for J?
Nm
What are other units for Pa?
N/m2
What is a positive control?
not exposed to experimental treatment but exposed to other treatments to produce expected effect
How do you find mechanical advantage?
(F without machine)/Force w/ machine
What does it mean to have a + work?
work done by system
How do you calculate efficiency?
Useful work/ energy input
How do you find the d of wave out of phase?
d=0.5(wavelength)+(wavelength)n
What are the units of k?
N/m
What is spherical aberration?
caused by imperfect surfaces (bends, ridges) and occurs in both lens and mirros
What is chromatic aberration?
Occurs as a result of diffraction so only occurs in lenses
What happens when an object is places at the focal points of a converging system?
no image created
(1/f)=1/o
Is a fully charges capacitor an open or closed circuit?
open
How do you calc absolute pressure?
Patm+pgh
What are three characteristics of ideal fluid?
- fluid and walls of container do not interact
- fluid is not viscous
- fluid exhibits laminar flow
What is the difference between an electric and mag field?
Electric field: any charge moving or not will generate E field
Magnetic field: all current carrying wires produce a mag field, strength is directly proportional to strengtj of current so can use it to measure current
What happens to E field, voltage, capacitance when introduce a dielectric metal?
E field decreases, voltage decreases, capacitance increases, charge increases
What happens if mag force is perpendicular to the path of particle?
will not alter speed so the particle will undergo circular motion (mv2/r)=qvB
What are three facts about mass spec?
- all particles enter mag field with constant/same velocity
- all of them are charged
- move in uniform circular motions and particles’ path radii determine mass-to-charge ratio
What happens to the mass of beta decay as a sample decays?
increase, but rate will slow down as more decays
What is the principle attractice force in nucleus? repulsive force?
- strong force: hold nuclues together
- electrostatic force: repulsion between neutron and proton
What does the graph look life of half-life plotted on y axis and time plotted on x?
linear function with slope of zero because half-life of a compound is constant
What type of lense is the eye?
a positive converging lense
What are the SI units for Boltzman constant (k)?
J/K
Does voltage change between 2 points depending on path taken?
no
What direction does current flow?
High to low voltage
What is the equation for force of mag field? How do you know if mag fields are attractive?
F=qvBsin(theta)
if current is in different directions
What are two facts about plane mirrors?
- ray of light hits plane mirror perpendicullary, will bounce back in same directions
- hit at angle, will reflect at same but opposite angle from normal
How do you find the Freq of a spring?
f=(1/2pi)(k/m)^(1/2)
What is another term for longitudinal waves?
compression waves
How many leters in m3?
1000L=m3
What angle is perfectly out of phase?
180 degrees
Do reflected rays of convex mirrors ever intersect? What is formed?
No, virtual upright images to the right is formed
How do you find PE of a particle?
PE=Fd
F=(kQq)/r^2
What must be true for a cart at top of loop not to fall?
Fc=Fg
Fn=0
What is the force equal to at bottom of loop?
Fc+mg=Fcircle
Fc=mv^2/r
What is the loop rule for 2 circuits in series?
- Voltage drop of whole circuit is equal to
- current through both is constant
- sum of voltages through each circuit is equal to voltage of circuit
- voltage drop higher for one resistor is larger resitance (V=IR)
What is the loop rule for circuits in parallel in a circuit?
- the voltage drop of that one loop is 0
- Voltage across resistors is constant/fixed, so cuirrent is not constant across resistors
- V1=V2=V3/Itot=I1+I2
- can find I for entire circuit by simplfying to one resistor, voltage drop of entire sustem is equal to voltage applied
What law explains why there cannot be greater 100% efficiency?
first law of thermodynamics states that energy cannot be created or destroyed so cannot have a greater output than what was supplied
How can you improve the effeiciency of bend light in converging lens?
increase n, and increase thickness of medium (increase strength of apparatus)
How would an index of refraction that depends upon the wavelength of transmitted light impact the performance of microscope?
imaged formed would not be focused because the effective focal length would differ for each wavelength and they would focus at many different points (chromatic abberation)
A strong wind lifts a 2-g leaf and propels it 3 m along a spiral path to reach a height of 2 m above the ground. What is the work done by gravity throughout this process?
Work in this case is the change in potential energy
(0.04J)
An ice cube is floating partially submerged in a glass of water. What happens to the height of the water in the glass as the ice cube melts?
It stays the same because according to Archemede’s principle, objects displace their weight in water as long as object is floating
What is the equation for effeciency? How do you convert power into energy?What is energy output equal to?
- Energy output/energ input
- E=PxT
- KE =energy output
A person pushes a 60 kg gurney starting from rest to the top of a 20 m long hospital ramp and brings it to a complete stop. If the ramp rises at a 30 degree angle from the horizontal and reaches a height of 6.5 m, then what is the net work done?
The gurney went from zero height to 6.5 m, and had an initial and final velocity of 0 m/s. The work done on the gurney is the change in gravitational potential energy, mgh, but gravity was doing equal and opposing work on the gurney the entire time hence why the change in kinetic energy is 0 J. So the net work done is 0J (since Wnet= ΔKE)
Sound waves have a relationship between oscillation and wave propagation that is:
Sound waves are longitudinal waves because ossilation is parallel to propogation
If unpolarized light travels through two identical polarized with an intitial intensity of 100kW/m2 what will be its final intensity?
it will be 50 because the first polarizer will cut in half but second one has no effect because oriented in the same direction as the first one
When white light moves from a vacuum to a glass prism, the component color that bends the most is:
Blue light because has the shortest wavelength, the greater the refractive index
What is the unit for mag field strength?
Tesla
What is the unit for capacitance?
Farad
How much work does a mag field perform on a charged particle?
0 because mag field always exerts a force perpendicular to the velocity and field. And for something to do work the force needs to be parallel to velocity (W=Fvcos(theta))
If a liquid is incompressible which law will it seem ideal?
continuity equation
A biophysics student is studying the human circulatory system. To make his calculations easier, he assumes that blood perfectly mimics an ideal fluid and ignores any diffusion into or out of circulatory vessels. If no mistakes are made, this student will estimate that the highest volume flow rate is displayed in:
Blood should travel through all vessels with an equal volume flow rate. Ideal fluids follow the law of continuity, which states that volume flow rate (VFR) is equal at every point in a system at a particular instant in time. Larger vessels will thus experience slower blood flow, while ones with smaller total areas will be moved through more quickly. In the end, VFR (measured in m3/s) is constant everywhere.
If Two ropes are holding a box, how do you find the tension in the rope?
Since rope is not moving the horizontal components are equal so
F1(cos(theta))=F2cos(theta)
What are two special right triangles?
30,60, 90
45,45,90
For something to float, what must be true?
Fb=Fg
How does specific gravity relate to something sinking or floating?
- if substance has a specific gravity greater than 1 it will sink
- if it has a specific gravity less than 1, it will float
How can you find the % of object submerged in water?
find specific gravity
How do body density and weight relate?
body density is inversly proportional to weight of displaced water. less denses, more water displaced so bigger bouyant force or weight displaced
How do you find the period of a spring? (pendulum motion)
T=2pi(m/k)1/2
What is hooks law of a spring?
F=kx
How do you find apparent weight? How do you find weight in air?
- Fg-Fb=weight in water
- Fg=dry weight
What is one requirement for the classive doppler effect to work?
angle cannot be 90 bc need to be parallel or antiparallel to find vel, will detect 0
Can transverse waves travel through vacuum?
yes (ie light)
How do you find intensity?
P/A
How can density change with concetrations?
higher concentration, higher density
What is the work done to move an object vertically up?
mgh
How does density relate to pressure?
2x mroe dense, 2x more pressure
How do you find percent composition from mole fractions?
multiply mole fractions by 100
How much work is done when a particle moves through a mag field?
0 because mag field is perpendicular to particle and work is only dont parallel to motion
What is the venturi effect?
Pair=PO2+pv2/V
Static pressure + flow pressure
Pair>P (air enters)
What is:
Sin(60)
cos(30)
sin (45)
Sin (60): .87
cos(30): .87
sin(45): .7
Where do electric field lines point?
direction positive charge will go
