U world Physics
The earliest stethoscope was simply a wooden pipe open at both ends. The fundamental frequency of a 0.25-m stethoscope will cause resonance at approximately what distance along the basilar membrane from its base? (Note: Use 350 m/s for the speed of sound in air.) A.7 mm B.16 mm C.25 mm D.32 mm
25 mm C.25 mm pipe length (pipe open at both ends): L = λ/2FIND WAVELENGTH** Therefore, the resonant wavelength is twice the given length L = 0.25 m of the stethoscope: λ=2L=2(0.25 m)=0.5 mF = v/λ= 350 / 0.5 m = 700 Hz From Figure 1, a frequency of 700 Hz would cause the basilar membrane to resonate around 25 mm from it base.
A large number of monoatomic ideal gas molecules are stored within a closed container at a temperature of 200 K. What is the average translational kinetic energy of the individual gas molecules? (Note: Use Boltzmann's constant k = 1.381 × 10−23 J/K.)
4.2*10^-21 ??????
Photorefraction with a camera at a distance of 50 cm away from a child produces a completely dark image of the pupil. If the child's retina is 2.5 cm from the eye lens, what is the lens strength of the eye? (Note: Use the thin lens formula, S = 1/o + 1/i.)
42 D
A patient's eye lens has a focal length of 2 cm. When the patient wears a pair of prescription eyeglasses with an optical power of −4 D, the combined strength of the lenses is approximately:
46 D
A voltmeter is placed across RL. If a charge of 0.1 C flows into the input node every 2 s, what will be the reading on the voltmeter? A.0 V B.50 V C.100 V D.200 V **do the math**
50 V
A swimmer enters a straight river at Point A and attempts to swim directly across to the opposite shore. However, the downstream velocity of the river is 0.5 m/s, which causes the swimmer to arrive at Point B on the opposite shore after 80 seconds of swimming. If the river is 30 m wide, what is the minimum diagonal distance between Points A and B? (Note: Assume the swimmer does not act to oppose the flow of the river.) A.30 m B.40 m C.50 m D.60 m *hint triangles* u better figure this out on ur own
50 m
Suppose the subject is holding a 4-kg ball during Experiment 1. Ignoring friction, what is the force exerted by the biceps? *you got this right b/c of educated guessing*
700 N (3 cm)(FB)=(20 cm)(45 N)+(30 cm)(40 N)=2,100 N⋅cmFB=2,100 N⋅cm/3 cm=700 N
negative frequency shift
A negative frequency shift means that observed waveform frequency decreases, which would only occur as blood flows away from the ultrasound device (ie, positive velocity).
positive frequency shift
A positive frequency shift means that observed waveform frequency increases. An increase in received waveforms would only occur as blood flows toward the ultrasound device (ie, negative velocity).
What is the frequency of the gamma rays emitted in PET? (Note: Use h = 4 × 10−15 eV⋅s.) emits 511 keV A.1.28 × 10^20 Hz B.1.28 × 10^17 Hz C.2.44 × 10^−9 Hz D.2.44 × 10^−12 Hz
A.1.28 × 10^20 Hz
A baseball traveling at 20 m/s strikes a player running at 5 m/s. The relative speed of the ball with respect to the player depends on the direction of travel of the ball relative to the player's direction of travel. What is the difference between the minimum and maximum possible speeds of the ball relative to the player? A.10 m/s B.15 m/s C.20 m/s D.25 m/s
A.10 m/s
The cardiac output of a subject is directly proportional to their: A.heart rate. B.vascular resistance. C.left ventricle volume. D.total blood volume
A.heart rate.
What is the camera lens' refractive index if incident light 50° from the normal is refracted to 35° from the normal? A.sin 50°/sin 35° B.sin 35°/sin 50° C.1/sin 50° D.1/sin 35°
A.sin 50°/sin 35° n1sinθ1 = n2sinθ2
Which of the following will occur if a corrective lens is placed in front of an eye that is unable to form a clear image of a nearby object? A) The image will shift away from the eye's lens B) The image will shift closer to the eye's lens. C) Spherical aberration will increase. D) Optical power will decrease.
B) The image will shift closer to the eye's lens. Hyperopia describes the refractive error that results in an individual being unable to see nearby objects. Hyperopia is caused by the optical power of the eye being insufficient relative to the length of the eye; the condition is corrected by placing a converging lens in front of the eye.
What is the period of an ultrasound signal that is attenuated by 20 dB after it travels 4 cm into soft tissue? A.5 × 10−9 s B.2 × 10−7 s C.5 × 10−6 s D.2 × 10−4 s
B.2 × 10−7 s
A 1-m spring is compressed to half its original length. What is the potential energy stored within the spring? (Note: k = 40 N/m) A.2.5 J B.5.0 J C.10 J D.20 J
B.5.0 J read carefully K= 40 N/m x = .5 (NOT 1) (.5) x 40 x (.5)^2
Circularly polarized light results from the vector sum of the electric field oscillations of two linearly polarized transverse waves traveling along the same axis. To achieve circular polarization, the two transverse waves must be out of phase to one another. The necessary phase difference is: A.0° B.90° C.180° D.360°
B.90° a wave polarized along the x-axis totally in-phase with a wave polarized along the y-axis produces a combined wave that is polarized between the x- and y-axes at a 45° angle.
Thin-film interference is observed when polychromatic light is incident on an interface formed when one semitransparent medium is layered on top of a second semitransparent medium. Which of the following best explains why thin-film interference generates a multicolored array when two semitransparent fluids are used? A.The density of the top fluid varies along the fluid interface. B.The thickness of the top fluid varies along the fluid interface. C.The osmolarity of the top fluid varies along the fluid interface. D.The two semitransparent fluids decrease the number of reflection events at the fluid interface.
B.The thickness of the top fluid varies along the fluid interface.
Ultrasonic shock wave devices may be used in medical settings to disrupt disease structures located deep in the body. Among other variables, the device user can control the frequency of emitted waveforms. The adjustment of waveform frequency: A.can be used to provide direct auditory feedback to the user. B.enables high-amplitude resonance within diverse target tissues. C.may eliminate the attenuation effects associated with tissue interfaces. D.assists in the measurement of bodily fluid velocity.
B.enables high-amplitude resonance within diverse target tissues.
For equally sized trocar-cannula systems, incisions made for blunt-tipped trocars are smaller than those made by sharp-tipped trocars, forcing the skin to stretch more around the cannula. This option better prevents slipping after the cannula is inserted because: A.it decreases the contact surface area. B.it decreases the static friction. C.it increases the normal force. D.it increases the coefficient of static friction.
C. increases normal force Why is D wrong? The coefficient of static friction depends only on the properties of the surfaces involved. Since both situations involve the same two surfaces (cannula and skin), the coefficient of static friction is the same.
Ultrasound imaging at 1.8 MHz is used to evaluate liver disease. The ultrasound signal travels through a boundary between liver and fat tissue at an angle of 30° relative to the normal at the boundary. If the ultrasound signal has a wavelength of 0.8 mm in fat tissue, what is the speed of sound in fat? A.720 m/s B.1250 m/s C.1440 m/s D.1660 m/s hint*v=λf
C.1440 m/s
Which unit ratio CANNOT be used to express the quantity of current traveling through a circuit? A.W·V−1 B.C·s−1 C.F·m−1 D.V·Ω−1
C.F·m−1
Which of the following procedures best describes the use of diffractive phenomena in separating the individual components of an electromagnetic wavefront? A.Single-slit diffraction of monochromatic light B.Double-slit diffraction of polychromatic light C.Grated diffraction of polychromatic light D.Grated diffraction of monochromatic light
C.Grated diffraction of polychromatic light Consequently, transmitting polychromatic light composed of light waves with different wavelengths (eg, white light) through a diffraction grate will produce a series of multicolored arrays (eg, rainbows) that enables an analysis of wavefront composition.
The researchers want to increase the work done by the subjects during the weight test. Which of the following changes to the test will increase the work by 50%? (Note: Assume the object is lifted straight up off the table.) A.Increasing the mass of the object by 50% and the distance the object is lifted by 50% B.Increasing the mass of the object by 25% and the distance the object is lifted by 25% C.Increasing the mass of the object by 25% and the distance the object is lifted by 20% D.Increasing the mass of the object by 100%
C.Increasing the mass of the object by 25% and the distance the object is lifted by 20%
The researchers want to measure the friction properties of the walking track using a block and a force gauge. They apply a force to the block, causing it to slide at a constant velocity along the track. What information is required to calculate the coefficient of kinetic friction for the track surface? A.Mass of the block, magnitude of the force, contact area between block and track B.Mass of the block, magnitude of the force, density of the block C.Mass of the block, magnitude of the force D.Mass of the block, velocity of the block, contact area between block and track
C.Mass of the block, magnitude of the force
That the spherical aberration of a converging lens is corrected by reducing the thickness of the lens periphery means that the light rays emerging from aberrant converging lenses: aberrant converging lenses: A.are insufficiently refracted at the lens periphery. B.converge at the lens focal point uniformly. C.are excessively refracted at the lens periphery. D.are scattered due to chromatic dispersion
C.are excessively refracted at the lens periphery. a perfectly spherical non-ideal lens produced multiple focal points -this can be fixed by altering the thickness at the periphery -abberation causes more extreme changes at the periphery, so that the area must be adjusted to lessen its impact Because reducing the thickness of the lens periphery will lead to less refraction of light, light rays exiting the periphery of a spherical converging lens can be said to refract excessively, converging on a focal point that is too close to the lens.
Capacitance equation
C= Q/V U (energy stored) = .5 CV^2
What is the force felt by a doubly ionized particle in a 2,000-N/C electric field? (Note: The charge of an electron is e = 1.6 × 10−19 C.) A.1.6 × 10−22 N B.3.2 × 10−22 N C.3.2 × 10−16 N D.6.4 × 10−16 N
Charged particles are accelerated in electric fields by a force known as the electric Lorentz force. The force exerted on a particle in an electric field is equal to the product of the particle's charge (q) and the electric field strength (E): F=qE The charge of a doubly ionized particle will be twice the charge of an electron (1.6 × 10−19):q=2(1.6×10−19 C)=3.2×10−19 C Using the above charge as q and the given electric field strength of 2,000 N/C as E, the force exerted on the particle is: F=(3.2×10−19 C)(2,000 NC)=6.4×10−16 N (Choice C) This value (3.2 × 10−16 N) is the force exerted on a singly ionized molecule. However, the question asks for the force exerted on a doubly ionized molecule, which has twice the charge and therefore experiences twice the force.
Many inhalational anesthetics are thought to increase surface tension effects in the alveoli. Water with greater surface tension: A.forms a convex meniscus in a narrow glass tube. .B.evaporates more quickly. C.has weaker van der Waals forces. D.creates droplets with smaller surface areas
D. Water in a glass tube forms a concave meniscus, not a convex meniscus. Liquids that form a convex meniscus, such as mercury, have surface tensions about 10 times greater than water. The surface tension of a liquid refers to the imbalance of intermolecular forces at its surface that makes its surface act as a thin, elastic film. Surface tension arises from cohesive forces (between like molecules) in a fluid. Water has relatively high surface tension compared to many liquids due its ability to form hydrogen bonds.
In one experimental trial, the projectile was uniformly accelerated from rest to a distance of 2 m in 0.1 s. What was the acceleration of the projectile? A.20 m/s2 B.40 m/s2 C.200 m/s2 D.400 m/s2
D.400 m/s2
What is the magnitude of the electric field generated in the acceleration chamber if the potential difference is 3,000 V over a distance of 50 cm? A.1.5 kN/C B.3.0 kN/C C.4.5 kN/C D.6.0 kN/C **do the math. u made a silly mistake**
D.6.0 kN/C
A scientist studying capillary fluid exchange in a laboratory environment can most effectively increase the net fluid filtration out of the capillaries by doing which of the following? A.Increasing the speed of blood flow B.Increasing interstitial hydrostatic pressure C.Replacing blood with a less viscous fluid D.Decreasing blood osmotic pressure
D.Decreasing blood osmotic pressure
When a subject moves toward the laser Doppler sensor during the walk test, the laser light reflected back to the sensor will be: A.lower in velocity than the light transmitted by the sensor. B.higher in velocity than the light transmitted by the sensor. C.lower in frequency than the light transmitted by the sensor. D.higher in frequency than the light transmitted by the sensor.
D.higher in frequency than the light transmitted by the sensor.
energy of light formula
E=hf E=Hv
force exerted on a particle in a uniform electric field
F=qE. The force exerted on a particle in a uniform electric field is equal to the product of the particle's charge q and the electric field strength E:
electric current formula
I=Q/t
Henry law of solubility
Low conc = Low solubility = Low blood-gas coefficient
power dissapated by resistors
P = IV = V^2/R = I^2R
The resistance of an object acting as a resistor is directly proportional to 1) Resistivity 2) Cross-sectional area 3) Length
R = pL/A 1 and 3 area is indirectly proportional
Doopler effect
The change in frequency of a wave as its source moves in relation to an observer
electric force and distance
The farther apart objects are, the weaker the force. The closer together the objects are, the stronger the force **if point A is 4 times greater in electric charge than point B, then the distance (2) for A is shorter by a factor or 2 (since r is squared)**
greater refractive index
The lower the critical angle the flatter the lens means light travels slower in the new medium
The propagation velocity of light is ____________________ of the photon energy
The propagation velocity of light is independent of the photon energy; it depends only on the medium through which it travels. Therefore, its velocity will not be affected by Compton scattering.
coefficient of kinetic friction
The slope of a line between two surfaces, relating frictional force to normal force (calculated by mass)
concave (converging) mirror
a mirror shaped like part of the surface of a sphere in which the inner surface is reflective they converge light rays to form real images in front of the mirror when the distance of the object is greater than the focal length.
convex (diverging) mirror
a mirror shaped like part of the surface of a sphere in which the outer surface is reflective diverge rays to form virtual images behind the mirror
Thin-film interference
a phenomenon in which a spectrum of colors is produced due to the constructive and destructive interference of light waves reflected in a thin film
center of mass
a point representing the mean position of the matter in a body or system.
After the load leaves the ramp, it slides on a horizontal table with a coefficient of kinetic friction μk of 0.1 and a coefficient of static friction μs of 0.3. If the direction of the load's velocity is positive, what is the acceleration of the load? (Note: Use g = 10 m/s2.) A.−3 m/s2 (12%) B.−1 m/s2 (42%) C.1 m/s2 (28%) D.3 m/s2 (16%)
answer is B ** ask dad** B.−1 m/s2**use coefficient of kinetic friction b/c moving (Because friction opposes sliding, kinetic friction causes sliding objects to decelerate so negative acceleration) F = -μkmga=Fnet/m = -μkmg/m = -μkga = - (0.1) (10) = -1 m/s^
ascribed status
assigned social position
Electric Field lines point ________ in positive charges
away Electric field lines point out from positive charges and into negative charges
an 8-f parallel plate capacitor generates a voltage of 5 v when fully charged. how much charge is stored by the capacitor? a.0.62 c b.1.6 c c.40 c d.100 c
c.40 c Q=CV charge= cap x voltage
speed of light equation
c= wavelength x frequency
Piezoelectric effect
describes the property of certain materials to create a voltage when they are mechanically deformed or when pressure is applied to them piezoelectric crystals produce sound when an alternating voltage is applied to them. It is reasonable to conclude that the expansion and contraction of the crystals will cause molecules in the surrounding medium to vibrate, creating sound waves.
Compared to other diffraction techniques, the advantage of x-ray diffraction is that it enables:
determination of three-dimensional molecular structure.
master status
dominates other statuses and thereby determines a person's general position within society
interstitial hydrostatic pressure
facilitates the inward movement of water from the interstitial space into the capillary
Cardiac output equation
heart rate x stroke volume
Electric Field lines point ________ in negative charges
into Electric field lines point out from positive charges and into negative charges
Doppler ultrasound
measuring blood flow in vessels via sound waves
monochromatic light...
monochromatic light is composed of only one color (ie, one wavelength). Consequently, the wavelength of monochromatic light can be detected without the use of diffraction.
A Nm/s is a unit of
power this is also kg/ (m*s^2) you need to know this conversion
blood osmotic pressure
pressure of plasma proteins "pulling" on water (opposes filtration)
speed of sound formula
speed = frequency x wavelength speed = distance/time
Lorentz force
sum of electrostatic and magnetic forces F=qvB
elastic potential energy
the energy of stretched or compressed objects
spherical aberration
the image defect of a spherical mirror that does not allow parallel light rays far from the principal axis to converge at the focal point, and produces an image that is fuzzy, not sharp
mechanical advantage
the ratio of the output force to the input force