BP/Kaplan/AAMC Physics Flashcards

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1
Q

A higher Reynolds number makes a fluid more likely to be

A

A higher Reynolds number makes a fluid more likely to be turbulent.

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2
Q

Increasing temperature decreases …

A

Increasing temperature decreases viscosity.

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3
Q

The Venturi effect says that when a tube narrows, the velocity …

A

increases and the pressure decreases. Thus, the narrow end of the tube has the lowest pressure and the larger end has the highest pressure.

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4
Q

The Reynolds number (which indicates the likelihood of turbulence) is directly related to …
Increasing the viscosity would therefore result in …

A

The Reynolds number (which indicates the likelihood of turbulence) is directly related to the velocity and density of the fluid and inversely related to its viscosity. Increasing the viscosity would therefore result in a lower Reynolds number and thus a smaller likelihood of turbulence.

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5
Q

density of water in g/cm^3

A

1, or 1000 kg/m^3

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6
Q

The law of conservation of energy states that

A

The law of conservation of energy states that energy is neither created nor destroyed, it only changes form. In other words, energy is only ever transferred. This example illustrates a transfer of energy from the bat to the ball, so it supports the law of conservation of energy.

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7
Q

DO U NEED the angle of incline to find work? which angle do u need? does work depend on path or no?

A

. The angle of incline is not necessary to calculate work done. The angle of importance is the angle between the force and displacement. The amount of work done to change the elevation of the object is independent of path.

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8
Q

For ramps, the ideal mechanical advantage can be calculated as follows:

A

For ramps, the ideal mechanical advantage can be calculated as follows: mechanical advantage = length of incline / height of incline. Intuitively we can picture that a ramp with a minimal angle of incline is going to have a very large length of incline to achieve a certain height of incline. The more we increase the angle of incline, the more we shorten the length of incline and decrease the overall mechanical advantage.

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9
Q

Moving a heavier box would also increase the amount of …

A

work that needs to be done, as the total change in potential energy of the box is now greater, therefore the amount of work that needs to be done on it to move it above your head will be greater as well.

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10
Q

work is…

A

Work can be a path dependent and a path independent variable. It depends on what type of force is being applied to do the work. Friction is a non-conservative force – work done against friction is path dependent. (google, prospectivedoc.com)

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11
Q

how do things move in electric field lines

A

A negatively charged particle such as an electron will move in the direction opposite the direction of the electric field lines; recall that electric field lines point away from positive charges and toward negative charges, which is the opposite of the way a negatively charged particle would move in the presence of those charges.

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12
Q

what does it mean if two pts are on the same equipot line?

A

The two points are located on the same equipotential line, meaning they are at regions of equal electric potential. Therefore, P2 – P1 must be equal to zero.

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13
Q

the charge gained e PE, so what does this mean? what are the units of electric potential? how can we find e potential?

A

The charge gained electric potential energy, and thus must have moved from a region of low to high electric potential. The units of electric potential are volts, or joules of energy per coulomb of charge. We know that the charge gained 12 joules of energy. Therefore, to find the electric potential we can divide the electric potential energy by the number of coulombs of charge moved.

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14
Q

The strength of a magnetic field generated by a moving charge is proportional to what? what does this mean in terms of speeds of particles

A

The strength of a magnetic field generated by a moving charge is proportional to the velocity and charge of that particle. A faster moving particle will generate a stronger magnetic field than a slower moving particle, given equal charge. Two particles of equal velocity will produce magnetic fields whose relative strength depends on their charge.

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15
Q

what is the lorentz force and what can it also be called

A

The Lorentz force is the electric force plus the magnetic force experienced by a charged object – also known as the electromagnetic force.

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16
Q

what cant magnetic fields act on

A

Magnetic fields cannot act on objects with a velocity vector that is parallel to the direction of magnetic field lines.

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17
Q

When considering the right hand rule for determining the direction of a magnetic field created by a moving charge, a person’s thumb will point in the direction of …

A

positive charge movement. This is the same direction as current’s flow through circuitry.

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18
Q

can a material with a large bulk modulus be compressed and what does this mean

A

A material with a large bulk modulus is not compressible, which means sound waves have an easier time traveling through the medium. a bulk modulus is the measure of a mediums resistance to compression

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19
Q

doppler effect eqn- when is the velocity of the SOURCE negative or positive?

A

The velocity of the source (vs) is negative when the source is moving towards the observer and positive when the source is moving away from the observer. Since the police car is moving towards Susan, the police car’s velocity is negative.

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20
Q

doppler effect eqn- when is the velocity of the OBSERVER negative or positive?

A

The velocity of the observer (vo) is positive when the observer is moving towards the source and negative when the observer is moving away from the source. Since Susan is driving away from the police, her velocity is negative.

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21
Q

what units are to be used for doppler eqn

A

use hz when doing doppler

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22
Q

what does the venturi effect state about liquid speeds and pressure exerted on surroudings

A

The Venturi effect states that when a fluid starts moving faster, it exerts LESS pressure on its surroundings.

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23
Q

True or false: The gauge pressure of my tires at sea level was 50 psi. After driving up into the mountains, I would expect the gauge pressure to drop slightly.

A

False. Gauge pressure is given by the equation: PG = PT - Patm , where PT is the total pressure and Patm is the atmospheric pressure. Driving up into the mountains should cause the atmospheric pressure to drop, but we would expect the pressure inside the tire to stay the same. Because gauge pressure is the pressure inside the tires compared to outside, we should have a HIGHER gauge pressure than we had before.

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24
Q

specific gravity

A

density of the liquid / density of water

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25
Q

density of water (know all of these)

A

1000 kg/m3, 1 g/mL, 1 g/cm^3, 1kg/L

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26
Q

concave meniscus

A

goes in. happens when adhesive >cohesive

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27
Q

convex meniscus

A

rounds out. happens when adhesive<cohesive

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28
Q

why is water more likely to form a convex meniscus

A

bc it has strong cohesive interactions

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29
Q

what can apply a bouyant force

A

Any fluid can apply a buoyant force, including all gases and liquids.

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30
Q

what type of harmonics can there be for closed tubes

A

For closed tubes, there can only be odd number harmonics.

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31
Q

ultrasound and ultraviolet waves are, respectively

A

longitudinal, transverse

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32
Q

does freq change when going btwn mediums

A

When light moves from a lower-index medium into a higher-index one, its velocity decreases and so wv must decrease too. freq doesnt change when going btwn mediums

33
Q

when can total internal reflection occur

A

Total internal reflection can only occur when attempting to transition the other way (from a high-index material into a low-index one).

34
Q

The magnetic field component of an electromagnetic wave is always:

A

Electromagnetic waves are composed of oscillating electrical and magnetic fields, oriented perpendicular to each other but both propagating in the same direction. The direction of propagation of an EM wave is perpendicular to both the electrical and magnetic field planes.

35
Q

what does the speed of an emag wave depend on

A

The speed of an electromagnetic wave does not depend on the intensity, color or polarization. it does depend on the medium

36
Q

sound waves are

A

longitudinal

37
Q

what kind of images will light rays hitting a plane mirror produce

A

Light rays hitting a plane mirror will produce virtual images as shown below.

38
Q

True or false: In a two lens system where the object has a height of 3 meters and the final image is upright and has height 2 meters, the magnification of every lens in the system multiplied together must equal 2/3.

A

This statement is true. Each lens in a two-lens system has a given magnification, which can be multiplied together to find the net magnification of the system. For the height of the final image of a system to be equal to 2/3 the height of the original object, all magnifications must multiply together to equal 2/3.

39
Q

True or false: In this ray diagram with a concave mirror, the location, size, and orientation of the image are correctly depicted.

A

This statement is false. The image for an object located outside a concave mirror’s center of curvature will produce a real, inverted image. The image shown in the question stem is incorrectly depicted as upright.True or false: In this ray diagram with a concave mirror, the location, size, and orientation of the image are correctly depicted.

40
Q

A two lens system is comprised of one lens with a magnification of -40, and a second lens with a magnification of ¼. An image created by this system will be how much bigger than its original object?

A

The net magnification of a two-lens system can be found by multiplying the magnification of each lens. The net magnification of this system is found by multiplying -40 and ¼, which equals -10.

41
Q

The conversion between focal length and diopters is:

A

The conversion between focal length and diopters is:

Diopters (1/m) = 1/Focal length (m)

42
Q

mirrors v lenses in terms of what they do

A

Mirrors fully reflect light, whereas lenses are primarily intended to refract light.

43
Q

A concave mirror has a focal length of 10 meters, and an object distance of 3 meters. Which terms accurately describe the image produced by this mirror?

A

Concave mirrors may produce real or virtual images. When a concave mirror reflects light from an object inside of its focal distance, the image is virtual, meaning that it appears to exist on the opposite side of the mirror where no rays of light are actually converging. Virtual images have a positive magnification, meaning that this image is upright.

44
Q

True or false: a real image is formed when reflected light converges toward a single point.

A

true

45
Q

what are mirrors defined by

A

Mirrors are defined by their ability to reflect light without refracting or absorbing it to any significant extent.

46
Q

plane mirrors only produce

A

virtual images

47
Q

power formula

A

P= IV=I^2R=V^2/R

48
Q

energy in terms of power

A

E= PT

49
Q

what is a real image?

A

real- describes an image on the same side of a lens or mirror as the refracted or reflected light that can be projected on a screen- in single mirror or single lens sytems, they are always inverted.

50
Q

what is a virtual image?

A

describes an image on the opposite side of a lens or mirror as the refracted or reflected light. in single mirror or single lens systems, they are always upright

51
Q

formula for resistance

A

R= densityL/A

52
Q

voltage drops of resistors in series and their resistances

A

Vs=V1+v2+vn
Rs=R1+R2+r3

53
Q

voltage drops of resistors in parallel and their resistances

A

Vp=V1=V2=V3
Rp=1/R1+1/R2+1/R3

54
Q

resistor

A

Resistor is defined as an electrical component which is used for controlling temperature and voltage

55
Q

capacitor

A

A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a capacitor is known as capacitance

56
Q

A glass fiber carries a light digital signal long distances with a minimum loss of amplitude. What optical property of glass allows this phenomenon?

A

Light can be carried along a distance within a transparent material by means of total internal reflection

57
Q

can sound waves travel in a vacuum

A

no, they require a medium

58
Q

An unknown solid weighs 31.6 N. When submerged in water, its apparent weight is 19.8 N. What is the specific gravity of the unknown sample?

A

The buoyant force on the solid is the difference between its weight (31.6 N) and its apparent weight in water (19.8 N). This force equals the weight of the water displaced, which, in turn, equals the product of the volume of the solid and the density of water. The specific gravity of the solid, i.e., the ratio of its weight to the weight of an equal volume of water, is then: 31.6/(31.6 -19.8) = 2.68. The correct answer is B.

59
Q

what is a harmonic

A

a half wavelength

60
Q

how to find the harmonics for an open pipe

A

the number of nodes

61
Q

how to find the harmonics for an closed pipe

A

number of quarter wavelength

62
Q

formula of a harmonic

A

fn = n * f1

63
Q

what are pitches related to

A

frequency

64
Q

Diverging lenses always have negative ______ _______.

A

Diverging lenses always have negative focal lengths

65
Q

The Doppler effect allows the observer to distinguish between

A

The Doppler effect allows the observer to distinguish between a stationary and a moving object that reflects ultrasound waves

66
Q

Capacitance in series circuits

A

1/c= 1/c1+1/c2

67
Q

capacitance in parallel

A

c= c1+c2+c3

68
Q

For maximum torque, a force should be exerted at a _____ angle to the lever arm. For maximum work, a force should be exerted at a ______ angle to the desired displacement.

A

90 degree, 0 degree

69
Q

all mirrors or lenses w positive focal lengths represent

A

converging systems

70
Q

to find efficiency u use what

A

w/qh or (qh-qc)= 1- (qc/qh)

71
Q

the bicarb ion can act as an acid bc

A

it has an acidic proton

72
Q

converging mirrors are concave but converging lenses are

A

convex

73
Q

when is the angle of incident greater than or equal to the critical angle

A

at total internal reflection

74
Q

Light can be carried along a distance within a transparent material by means of

A

total internal reflection.

75
Q

what does electrical force depend on

A

Electrical force depends on the particle’s charge and the strength of the electric field experienced by the particle, not on the particle’s speed

76
Q

The intensity level in decibels is defined as 10 log10(I/I0), where I0 is a reference intensity equal to the human threshold of hearing, 10–12 W/m2. What is the intensity of the threshold of pain, 120 decibels?

A

Because the intensity level is 120 dB = 10 log (I/I0), log (I/I0) must equal 12 and I/I0 must equal 1012. Therefore I = 10° W/m2, because I0 = 10-12 W/m2.

77
Q

hen a ray enters going from a lower refractive index (air) to a higher (bead) it should bend towards the

A

hen a ray enters going from a lower refractive index (air) to a higher (bead) it should bend towards the normal.

78
Q

if the object is beyond the focal length what is the nature of the image

A

real and inverted