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)