Physics- Uworld

For each 10-fold decrease, sound intensity decreases by what amount of dB? a 100-fold decrease, corresponds to a decrease by what dB

10-fold decrease, sound intensity decrease by 10dB 100-fold decrease, decrease by 20dB

Acceleration of gravity on moon is one-sixth that observed on earth's surface. how long would it take for the object launched in the moon?

6 times longer. an object launched vertically from surface of moon would take 6 times longer to return than an object launched vertically from surface of earth.

Continuity eqt

A1v1= A2v2

When side of an open tanked filled with water is punctured, water flows out according to Bernoulli's eqt. If water flows out at rate 6m/s, height of water above the hole?

A: 1.8m PE= pgy1. KE= 1/2pv^2 based on conservation of energy for fluids. Can cancel out some terms, P1 and P2 both equal to atmospheric pressure, cancel out. Velocity at which water level falls is much lower than velocity leaving through the hole v1 << v2, so v1 and 1/2pv1^2 is negligible, equal to 0. Set height of hole to be reference elevation, y2 and pgy2 also equal to 0. eqt simplified to pgy1= 1/2pv2^2 indicating PE above the hole is equal to KE out the hole. Cancel p from both sides, use g= 10m/s2 and v2= 6m/s. 10m/s2 x y1= 1/2 (6m/s)^2 solve for y1= 1/2 (36) / 10= 1.8m

Baseball travel at 20m/s strikes player running at 5m/s, what is the difference between minimum and maximum possible relative velocities between ball and player?

A: 10 m/s think vector in same direction (minimum) player 5m/s and ball 20m/s take 20-5= 15m/s in opposite direction (maximum) player forward 5m/s and ball 20m/s in opposite way 20+ 5= 25 take the difference get 10m/s

After experiment progressed for 2 min, liquid in thermometer rose 2mm. How high will liquid rise from 25C mark after experiment progressed for 4 min?

A: 10mm Graph: at 2 min, it increases temp from 25 to 27, and rise 2mm At 4 min, it rises temp from 25 to 35, and rise how much? Thermal expansion eqt: delta L= alpha x L x delta T L or V (expansion of a substance) is linearly proportional to its change in temp. AL= delta L/ delta T 2mm/2C= 1 mm/C delta L= 1mm/C x delta T =1mm/C x 10C= 10mm this said height of liquid increases by 1 mm for every increase in 1C. At 4 min: it increases by 10C, so it increases 10mm.

For a pipe open on both ends, fundamental frequency of a 0.25m pipe will cause resonance at approx. what distance along the membrane? use 350m/s for speed of sound.

A: 32mm first, find frequency. f= v/2L. 350m/s divides 2 times 0.25m= 700 Hz. Meter cancels out, get 1/s which is Hz. Psg: locate the Hz found on the figure and find its distance.

Mass of 80kg person is suspended by their arms on earth. What is approx. TENSION on lumbar disc 1? gravity is g=10m/s2 What is tension force and role in maintaining which type of eqlb

A: 400N Weight= mg= 800N person is suspended above the ground, so force opposing gravity must be TENSION T experienced by discs and other tissues. Figure show lumbar disc 1 is located closed person's midpoint. So half of person body mass located below lumbar disc 1. T= Mg/2= 40N. For objects suspended in air, weight of object is typically encountered by a tension force that maintain STATIC EQLB

How much heat in kJ released from combustion of 1g sample? what equation to use?

A: 40kJ use q=mcdeltaT q= HEAT required to change the temp of a substance m= mass c= specific heat (amount of heat reqd to increase 1g of substance by 1C) Psg: 500 g water c of water= 1 cal/gC maximum temp change delta T is 10C. Figure indicated highest temp is 35C and lowest is 25C. Q= 500g x 1cal/gC x 10C= 5,000 cal. Convert cal to kJ using conversion provided in passage. 1,000 cal= 4.2 kJ q= 5,000 cal x (4.2 kJ/1,000 cal)= 21 kJ

Distance of 50cm, image is 2.5cm, what's the lens strength of eye? use thin lens formula S = 1/o + 1/i

A: 42D Convert cm to m 1/0.5m + 1/0.025m= 2m-1 + 40m-1= 42 D

Object with 5kg mass M is suspended with a cable and its tension is 45N. What's magnitude n direction of force of friction between mass and and wall?

A: 5 N, upward tension force 45N on the cable is trying to pull up the mass. Mass also have weight/gravitational force= mg= 5kg x 10m/s2= 50N. gravitational force 50N downward force (-) acting on the mass is greater than 45N tension force pulling the block upward (+y), so then frictional force must be act in opposing, upward (+y) direction to maintain STATIC EQLB. sum of all forces= up forces + down forces= 0 (+45N + Ff) + (-50N)=0 Ff= 50N -45N= +5N

what is specific gravity equation? bone sample with sp. gr =3 completely immersed in alcohol sp. gr= 0.8 is subjected to a Fb= 4N. what Fb for bone when immersed in water?

A: 5N specific gravity= density of substance/ density of water find density of alcohol= specific gravity of alcohol x density of water =0.8 x 1kg/L= 0.8 kg/l for an object fully immersed in 2 different fluids V1 and V2. Volumes of fluid displaced in each are equal to volume of object V1=V2=Vobj hence, ratio of buoyant forces is equal to ratio of fluid densities Fb1/Fb2= (p1V1g)/(p2V2g) cancel out V1 and V2 and g, gets Fb1/Fb2= p1/p2 Fb, alcohol/Fb,water= palcohol/pwater solve for Fb,water= Fb, alcohol x (p-water/p-alcohol) note: Fb, alcohol given in qs stem. = 4N x (1kg/l)/0.8kg/l= 5N

2 convex lens are placed in series st. Image produced by 1st lens becomes the object of 2nd lens. If each lens is capable of producing a 3-fold magnified image, what's the maximum magnification that this 2-lens system can provide?

A: 9 For multiple lens placed in series (not in direct contact), the magnification of lens series is a product of each lens' individual magnification: Mtotal= M1 x M2 x...Mn (multiplying)

Which values gives the number of parts per million (ppm) of Nacl in a 0.90% saline solution?

A: 9,000 basis for ppm= 1,000,000 parts/ basis for percent= 100 parts = 10,000 ppm/1% 0.9% NaCl x (1,000,000 ppm/1%)= 9000 ppm NaCl alternatively, x ppm Nacl = 0.90% NaCl x g Nacl/1,000,000 g water = 0.9 g Nacl/100 g water solve for x.

Absolute temp of ideal gas molecules stored in a container is directly proportional to the:

A: Average KE of gas molecules Exp: T is proportional to average KE of each molecule/quantity of molecules determined not by KE of any one gas molecule but rather by avg KE of ALL gas molecules.

Fat tissue has a lower electrical conductivity than lean tissue. For same amount of current (I) entering body, relatively HIGH body fat content would be indicated by:

A: a higher voltage difference across body Electrical conductivity: how easily a current can move thru a material, talking about I, so its inverse to electrical resistance R. fatty tissue is less conductive, meaning it's MORE RESISTANCE. V= IR I same, if R increases then Voltage also increase.

What happened when astronaut accidentally hit a protruding portion of spaceship with her foot:

A: continues along her original path while spinning about her center of mass. Torque= rFsintheta upon striking the protrusion of ship, her foot experiences an impact force due to collision. The foot, leg and torso acts as the lever arm btwn impact force and her center of mass. The collision generates a torque about her cm making her spin!

Studying capillary fluid exchange, what a method to effectively increase the filtration of fluid OUT of capillaries:

A: decreasing blood osmotic pressure Hydrostatic pressure: fluid moves away from areas of high hydrostatic pressure and toward areas of low hydrostatic pressure. Capillary hydrostatic pressure promote movement of fluid OUT of capillaries vs. interstitial hydrostatic pressure diminishes movement of fluid out of capillaries osmotic pressure: created during osmosis by diffusion of SOLVENT across a semipermeable membrane separating compartments of different solute concs. ***Fluid moves from areas of LOW osmotic pressure (insterstital fluid) to -> areas of HIGH osmotic pressure (blood). ***osmotic pressure of blood is greater >> osmotic pressure of interstitial fluid. Hence, if decrease osmotic pressure in capillary (ie. Reduced conc. Of plasma proteins or salts) would increase the movement of fluid OUT of capillary.

Unassisted expiration is possible under the effects of anethesia and during normal expiration is due to what effect that allows the lung to return to original shape:

A: elasticity of pulmonary tissue Pulmonary resiliency (elastic recoil and surface tension effects): allows for passive expiration and does not require muscles or ATP energy.

For noise cancelling earphones, which generates a waveform that reduces the intensity of ambient noise through wave interference. With sound wave, the waveform generated for complete cancellation will be:

A: flipped across x-axis intensity (perceived loudness) of a sound wave is related to its amplitude (displacement). when more than 1 wave occupies same space, wave interference occurs to create 1 wave that's the sum of individual waves. 1. Constructive interference occurs when sum of amplitude results in a LARGER AMPLITUDE. Ex: A wave summed with an exact copy of itself. 2. Destructive interference occurs when sum of amplitude results in a SMALLER AMPLITUDE. Ex: complete noise cancellation, resulting in an amplitude of zero) a wave that is flipped across x-axis have equal and opposite amplitudes so their sum is zero, resulting in total destructive interference and canceling all noise.

How does the partial pressure in the capillary change as anesthesia is admistered?

A: graph should increase then level off (exhibit log graph) when anesthesia is first administered, its partial pressure is greater in the lungs and therefore it will diffuse into the capillaries. Capillary partial pressure WILL BUILD UP along length of capillary as blood flows through it. Alveolar partial pressure doen't change significantly bc the volume of gas in the lungs is much greater than volume of gas in capillaries. As PP in capillary incrase, PP difference across membrane driving diffusion will decrease. Rate of diffusion will decrease and eventually reach ZERO when capillary and alveolar PP are equilibrated.

A positive pressure mechanical ventilator most likely inflates the lungs by directly:

A: increasing alveolar pressure! Normal inspiration: contraction of diaphragm (it pulls down), volume of pleural cavity increases and intrapleural pressure (IPP) decreases. Lungs expand to fill pleural cavity and AIR FLOW INTO the lungs. B/c normal inspiration is initiated by decreasing IPP, this pressure mech is referred to as negative pressure breathing. During anethesia: diaphragm can't initiate inspiration by decreasing IPP. Instead, positive pressure ventilator directly pumps air into the lungs, this cause increases alveolar pressure and cause lungs to inflate.

What happened to sound's intensity and velocity when it passes from air to solid?

A: intensity decreases, velocity increases. Intensity: when sound crosses from one medium to another, a portion of wave's energy is reflected. Hence, it loses energy and their intensity decreases when it passes from air to a solid structure. Velocity: velocity increases with temp. Gases (slowest), liquids (faster), and solids (fastest)

An object with same density as water is stationary and suspended in a container filled with water. Ignoring effects of fluid friction, what will happen to object after a downward force is momentarily applied?

A: the object will sink at a constant velocity With force applied: velocity increases. Then force is removed, velocity remains constant. Obj that is suspended (submerged an stationary) is neither sinking or rising b/c it has same density as surrounding fluid. hence, initial net force is zero, and object initial velocity is zero. downward force applied to obj, net force on obj is downward. Obj will sink and its velocity in downward direction increases with time (accelerates) as described by Newton's 2nd law. F=ma the moment after applied force is removed, net force acting on obj returns to zero. In absence of net force, an obj at rest v=0m/s will stay at rest and an obj in motion at a given velocity will stay in motion at same velocity (Newton's first law). Hence, obj continue to sink at a constant velocity.

Oxygen is most EN element of group 6A. But it also has the lowest electron affinity in the group. What factor can be used to explain this discrepancy?

A; oxygen's valence electrons experience more electron-electron repulsion than other group 6A elements. Electron-electron repulsion result in a decreased electron affinity.

A graph of pressure and volume, the area enclosed by the loop is represented by what variable:

A= P x V= work

Define Archimedes principle and eqt for fraction submerged. Psg: avg density of human fatty tissue 0.9 kg/L and density of water 1 kg/L. A 0.3kg object with half the density of human fatty tissue placed in water. What percentage of mass is submerged?

An object in a fluid experiences an upward buoyant force equal to the weight of displaced fluid. obj density << fluid density, obj float. For a floating obj, the fraction submerged is ratio of obj density/fluid density. Fraction submerged= p-obj/p-fluid obj's density is half of human fat is 0.9/2= 0.45 kg/l. obj density 0.45 is less dense than water 1kg/l, obj float and partially submerged. 0.45kg/l divide 1kg/l= 0.45 x 100= 45%

relative to angle of incidence, how will angle of refraction changes when a monochromatic ray of light enters a medium of greater refractive index?

Angle will decrease b/c light travels slower in new medium

Which group of blood vessels is the main source of peripheral resistance?

Arterioles, b/c they experience the largest pressure drop.

What force act on the fluid when stirring it? what force act on fluid when stop stirring?

As static fluid is stirred up, energy transferred into KE associated with motion of fluid. At first it is laminar but then become turbulent as velocity of fluid increases. Once stirring stop, the only force actin on flow is the viscous shearing force

3 characteristics of sound wave: What is attenuation? Is greater or lesser for softer materials? Is it increase or decrease with distance, what eqt referred to? what medium can sound not propagate through and which one it can and at what speed? What kind of wave is sound? Longitudinal or tranverse? A pressurized or not wave?

Attenuation: decrease in amplitude (or intensity) of a wave due to absorption and scattering. It depends on properties of medium. Attenuation is greater for softer material (or attenuated most) A longitudinal pressure waves.

Similarity of electric force and intensity of sound

Both are 1/r squared (inverse square) -exponential graph

Fundamental wave, wavelength and frequency of pipe open at BOTH ends vs. pipe CLOSED at one end

Both ends: wavelenth= 2L/n= 2L f= v/2L End end: wavelength= 4L/n = 4L f= v/4L

Specific heat of water, c

C= 1 cal/gC

What 2 factors multiply to get cardiac output? Define cardiac output.

CO= Stroke volume and heart rate. The volume of blood pumped by the heart every min.

What kind of image does concave produce? Real or virtual? what kind of images does convex produce?

Concave (converging) mirror produce REAL image. It's focal point come together in front of mirror. Convex (diverging) mirror produce VIRTUAL image. It's focal length behind the mirror. If the light rays are reflected at a smaller angle, these rays can be traced back behind the mirror to a more DISTANT focal point. Bc radius is twice the focal length, it has a larger radius of curvature.

Concave lens is a ____ lens vs. Convex lens is a ___ lens

Concave is a diverging lens (go to a cave to dive) creates UV images convex is a converging lens

Convection vs. conduction

Conduction: transfer of heat thru direct physical contact ie. Holding cup of coffee convection: transfer of heat thru the flow of fluids. Fluids absorb heat from hotter regions and give it to colder regions ie. Hair blowing

Water with greater surface tension:

Creates droplets with smaller surface areas. Water molecules at surface experience a net inward force, this decrease surface area of water and pull it into an approx. spherical shape. High surface tension indicates high cohesive forces. Water is more attracted to itself than to the other surface. High adhesive forces (water to glass) vs. cohesive forces (water to water). Water with greater surface tension will also have stronger van der waals forces.

Which alkali metals has the lowest ionization energy, does this mean it's more or less or most reactive?

Cs has lowest ionization energy (less/least energy required to remove an e- from valence shell) so it is most reactive with nonmetals! As going down the group, size n gets larger.

Eqt for first law of thermodynamics

Delta U= Q + W Q is amount of heat W is work done to the system by surrounding If no direct heat transfer, Q=0 U=W W= P x delta V. P= pressure

Resonant frequency and pitch relationship: a sound with high frequency is perceived to have a high or low pitch?

Direct relationship! Frequency of a sound is associated with its perceived pitch (or tone). Resonant frequency depends on physical characteristics and geometry of object. Not related to intensity. High frequency sounds have high pitch, vv.

When a sound source moves towards you, what happens to the observed wavelength and frequency? what effect is this?

Doppler effect. Move toward you: wavelength decreases and frequency increases (inverse) velocity= wavelength x frequency

E= hf, what is energy of a photon is proportional to?

E is proportional to frequency. Ex: a photon's frequency will decrease as its energy decrease. Velocity of a photon's propagation is not related to photon energy. Instead of a photon moving in a straight path as expected. If there's a deflection of photon in the path, will make angle and traced back as the point of origin to appear at a different location.

Eqt for uniform electric field

E= delta V/d E, unit newton/coulomb N/C equivalent to Volts/m d= distance, unit meter

What is bond dissociation energy? What is it related to? And which type of bonds are stronger and require more or less energy to break?

Energy to break a chemical bond between 2 atoms. Related to bond length or the distance between nuclei of 2 bonded atoms. Shorter bonds are stronger and require more energy to break require more energy to break double bonds than single bonds. Ex: C-C longest, weakest and require least energy to break (low bond dissociation energy)

Relationship between electric force and distance separating each charge:

F-e = 1/r squared Inverse square function. An exponential relationship

What's meant by kinetic friction and static friction?

F-k occurs when 2 surfaces slide. F-k= u-k x N F-s occurs when surfaces are not sliding.

Eqt for static friction

F-s= u-s x N F-s = static fiction u-s= coefficient of static friction N= normal force Slipping can be prevented by increasing normal force. Greater normal force produce a greater static frictional force.

Electric Lorentz force vs. magnetic Lorentz force

F= qE vs. F= qvB

Qs asked to balance the eqt, given the molecular weight C g/mol. If x mol of A mixed with same x mol of B, what approx theoretical yield of C?

First, balance it! take x mol of A multiply by mole ratio (C/A)= mol A do the same for x mol B, Whichever yield the least product/smaller value is the limiting reagent. Then use the LR mol and multiply it by molecular weight g/mol to get g of theoretical yield.

Define Pascal law. Eqt of pressure.

For a static, incompressible (constant density) and fully enclosed fluid, an external pressure applied to fluid will be uniformly transmitted to all surfaces. Hence the applied force is experienced by all surfaces of fluid, including the force gauge. P= F/A measure of a force exerted over an area. Ex: P1 applied by LVAD equate to P2 experience by force gauge P1=P2 F1/A1= F2/V2 for 2 equal pressures, a GREATER FORCE will be exerted to a larger area, vv. So then F2/F1= A2/A1 (ratio of forces equal to ratio of their respective areas). depend on figure: gauge area A2 is half area of LVAD A1. So then force experienced by force gauge is also half LVAD force, a ratio of 1:2.

Refractive index increase with what property? -amplitude, frequency or wavelenth

Frequency Ex: violet is higher in frequency than red. So violet light will refract more

Eqt of fundamental frequency of a string fixed at both ends ie. Violin

Frequency of 1st harmonic n=1 is called fundamental frequency, f1. F1= v/wavelength wavelength= 2L/n. N=1 for first harmonic. F1= v/2L

If have 120g per 100 ml, given its molar mass, asking for molar conc? How to approach

G/ml x (1000ml/L) x (mol/g) = mol/l Don't forget can use volume conversion of 1000ml/L

Flexing the ball up and down gives up what graph of torque and angle: arm at the 90 degree, sin90= ?

Has a hump with 90 degree at the highest point/ torque. sin90=1 (maximum value)

Sound energy is propagated in the form of pressure waves, not __ waves or __ waves:

Heat waves or electric waves

Concentration C of a gas dissolved in solution is described by which law?

Henry low of solubility. C= k-h x P-gas highly soluble substances dissolve easily in blood, and hence higher conc are required to reach target threshold partial pressure. Vs. poorly soluble gas will require a low conc. In blood to take effect.

Voltage kept constant. Frequency is increased from 200Hz to 400Hz, how much does I change?

I doubles (2I) when resistance is half. Freq at 200Hz is 400 ohm Freq at 400Hz is 200 ohm Resistance is half. V=IR I= V/R I= V/(R/2) I= 2V/R

Eqt for intensity of sound wave:

I= P/A P= power A= area 4pi x r squared I = 1/r squared (inverse square of distance between source and detector) Exponential graph. Significant decrease in intensity as the distance increases.

2 eqts to use if finding V. If given charge in unit C and time, s. Resistance is given in passage.

I= Q/t V= IR

Photon wavelength increases by 50%, or a factor of what ?

Increase by 50%, or a factor of 1.5 or 3/2.

Dielectric substances increase or decrease capacitance? What is dielectric constant (k) of a vacuum? Does the capacitance increase, decrease or same and by how much if the dielectric constant (k) for material is 1.5? if k is 2?

Increase capacitance! C= k times C-o K-vacuum is 1.0 K= 1.5, capacitance will increase by 50% (not 100%) k=2, capacitance increase by 100%.

In an isoelectronic series (same # of e-), how to determine size based on which relationship between ionic radii and atomic number?

Ionic radii decrease as atomic number increases (inverse) Ex: sulfur has the lowest atomic # (fewest # of protons), it has smallest Z-eff making it the LARGEST ion.

If angle of inclination increases, what happened to kinetic friction?

Kinetic friction decreases b/c the weight component of perpendicular to the ramp decreases.

What does the kinetic frictional force depends on what factor:

Kinetic friction depends on an object's mass. Friction is not affected by size of contact surface or speed.

In which medium does light travels the fastest and slower? -vacuum -transparent materials eqt of index of refraction.

Light travels fastest in vacuum and slower in transparent materials. N= c/v the higher the index of refraction, the slower light travels through a material.

Direction of magnetic force on a moving ion is perpendicular or parallel to both ion's velocity, v and direction of magnetic field, B: vs. the force due to an ELECTRIC field is parallel or perpendicular to direction of electric field, E.

Magnetic force is PERPENDICULAR to both velocity and magnetic field. Cross product of 2 vectors is a vector perp. To both vectors. Use right hand rule. Electric force is parallel to direction of electric field.

phase shift

Measure of the offset of a wave from a reference wave.

Eqt for mechanical advantage

Mechanical advantage= Fo/Fi= di/do ratio of input distance to output distance Ex: hand holding a ball -hand center of gravity: distance from elbow (output) is 30 cm -biceps attachment: distance from elbow (input) is 3cm di/do= 3cm/30cm= 0.1 mechanical advantage of biceps is <1, which means that a relatively large input force from the biceps is required to balance an opposing force at the hand.

At melting/freezing point, does it exist as ice, liquid or both?

Melting/freezing point of water is 0C, it exist both as solid ice and liquid water unless heat is added to or removed from mixture. Latent heat of fusion: amount of heart required to convert solid at its melting pt tempt to its liquid phase by breaking bonds. heat released from combustion rxn will first go toward latent heat of fusion to melt the ice into liquid water. Temp of water will be constant at 0C as long as ice is still present and temp will not start to increase until ALL ice melts. Hence, temp of water begin to increase AT A LATER TIME.

More gamma rays = ______ intensity, higher or lower? Eqt for intensity.

More gamma rays= HIGHER intensity. Intensity= P/A intensity of electromagnetic radiation increases with higher indiv photon energy and higher emission rate.

If index of refraction is higher in second medium n2, light refract toward or away from the normal? vs. index of refraction is lower?

N2 > n1: toward normal n2 < n1: way from normal.

Object slides on horizontal table, given a coefficient of kinetic friction and static friction. If direction of obj's velocity is positive, what Newton's law considered and how that affect acceleration and net force?

N= W, normal force (up) equal weight W= mg F-k= u-k x N F-k= u-k x mg Newton's second law: F= ma a= Fnet/m **direction of obj velocity is positive and friction acts in opposite direction. Net force and acceleration are negative, Fnet= -F-k a= -u-kmg/m cancel outs m = -u-k times g

In a contraceoup injury, due to what Newton's law?

Newton's first law: Object's inertia is its resistance to changes in its velocity: objects tend to stay in motion or stay at rest. due to brain's inertia, brain can continue to move independently of skull and cause injury

Open system vs. closed system vs. isolated system

Open: allow both matter and heat to be exchanged. Closed: heat can be exchanged but matter can't. Isolated: no heat or matter can exchange. Bomb shell act as closed system Calorimetry device: act as isolated system.

3 eqts for electric power

P= IV= I^2R= V^2/R tips: first remember its IV fluid then use first variable: I squared times R then use second variable V squared divide R. times first then divide. Power dissipated is released as Heat!

What is eqt for hydrostatic pressure?

P=density x gravity x height P=pgh note: can ask to calculate total height minus height of given point.

Does parallel circuit have different or same voltage? Then look for either I or R

Parallel circuit have SAME voltage across them. set 2 voltages equal to each other. IR= I2R2 Psg: give graph of capacitor resistance vs. signal frequency. It indicates at what signal frequency, then find R.

What is volumetric flow rate Q equal to? what is equation of Q?

Q is equal to cardiac output, unit mL/s -find CO 1ml= 1cm^3 so Q= cm^3/s volumetric flow rate= cross-sectional area x flow velocity Q= Av A=pi x r squared then solve for v

Equivalent resistance in parallel vs. series

R-eq= R1 + R2 + Rn. Ex: multiply R by n 1/R-eq= 1/R1 + 1/R2 Ex: multiply R by 1/n

Equation for resistance of a resistor. Resistance is direct proportional to which terms and inverse to which terms?

R= p x (L/A) R = resistance p= resistivity L= length A= cross-sectional area Direct prop to resistivity and length but inverse to its cross sectional area.

Venturi effect

Refers to reduction of fluid pressure that occurs when flow velocity increases at constricted sections of a tube. This effect is irrelevant to pressure in alveoli and lung exhalation. In fact, constricted airway can cause significant reductions in pressure that cause them to collapse.

Define stroke volume. How to determine that on cardiac PV loop? Define heart rate. What unit is HR? What variable can used to convert it to right unit?

SV: volume of blood that is ejected from left ventricle in one cardiac cycle. On cardiac PV loop- SV volume is the difference in volume between initial and end of ejection. Ejection start occurs when LV volume is decreasing with an increase in pressure. HR: Number of cardiac cycles/min. Given frequency of Hz, which gives cycle/s multiple it by (60s/1min)= cycles/min multiply SV by HR to get ml/min

What is refractive index if incident light 50 degree from the normal is refracted to 35 degree from normal?

Sin50/sin35 based on Snell law: n1 sin theta 1= n2 sin theta 2 solve for n2. Set n1=1

Single-slit diffraction produces a pattern of dark and bright bands that is associated with what properties?

Slit width and wavelength of light. Not refractive index of medium. N is relevant to refraction, dispersion, or other that related to passage of light between 2 media.

How to find total length strength S of multiple lens placed immediately adjacent to one another. How to find total power of lens

Stotal= S1 + S2 + Sn (adding) Ptotal= P1 + P2 + Pn (adding) sum of individual lens powers

What is the period of a wave? its unit? Eqt?

The period is the amount of time (s) required for one complete cycle or oscillation. Unit of seconds. T= 1/f

After astronaut leaves earth surface and enter obit, what happened to them?

Their center of mass is shifted.

Plot of velocity (y-axis) vs. time (axis), what's the displacement or distance travelled?

To find displacement is to find area under the curve. Displacement equal to total distance traveled. Ex: find area of rectangle (bh) or triangle (1/2bh)

shock wave therapy

Use high frequency waves to cause destructive, high amplitude vibration within target structures. For maximum effectiveness, frequency of shock waves should match resonance frequency of target structure.

What is work done by frictional force when the object slides down the entire length L of ramp and then push it back up to original position?

W= Fd W= F(2L) when object slides down: kinetic friction tried to keep it from sliding down by pulling the opposite way. when object is pushed up to top, kinetic friction tried to pull it down ramp with pulling it opposite way of motion.

With applied force, what changes to the friction on the graph?

With applied force initially, has a linear line increase associated with static friction. Once at its peak (threshold of motion): upper limit of static friction > kinetic friction. then object starts to move: the kinetic friction decreases sharply and remain constant.

If enthalpy of products is lower than enthalpy of reactants, energy is released and what sign is delta H and endo or exo? Entropy of gases vs solid

delta H is negative and exothermic when heat is released. solids have low entropy: its structure is ordered and motion is constrained. vs. Gases have high entropy, more disordered and less motion constrained. Increase of entropy: solid to liquid to gas. Disorders increase, hence delta S is positive.

What is buoyant force equal to? Eqt.

the weight of the displaced fluid Fb= p x V x g P= density of water V= displaced volume g= gravitational acceleration find volume of displaced water V= Fb/pg 660N/ (1kg/L) x 10m/s2= 66L