# Shared Flashcard Set

## Details

Physics MCAT
Kaplan study points
165
Physics
01/12/2009

Term
 rules for powers of ten
Definition
 multiply number, add exponentsdivide numbers, subtract exponentscan only add/subtract numbers with same exponent
Term
 SOH CAH TOA
Definition
Term
 When does sinθ or cosθ = 0?
Definition
 sinθ = 0 at 0° and 180°cosθ = 0 at 90°
Term
 When does sinθ or cos θ = 1/2?
Definition
 sin30 = 1/2cos60 = 1/2
Term
 When does sinθ and cosθ = √2/2?
Definition
 45°
Term
 When does sinθ and cosθ = √3/2?
Definition
 sinθ = 60°cosθ = 30°
Term
 scalar
Definition
 have magnitude but no direction
Term
 vector
Definition
 has both magnitude and direction
Term
 Steps to find a resultant vector
Definition
 resolve vectors to be summed in x and y componentsadd x componentsadd y componentsfind magnitude using v = √vx2 + vy2
Term
 displacement (Δx)
Definition
 vector quantity that describes change in position
Term
 average velocity
Definition
 displacement vector over time
Term
 instantaneous velocity
Definition
 average velocity as Δt approaches 0
Term
 average speed
Definition
 scalar quantity of distance traveled over time
Term
 acceleration (a)
Definition
 rate of change of an object's velocity
Term
 How do you find an object with linear motion's velocity?
Definition
 v =  v0 + at v2 = v02 + 2aΔx
Term
 How do you find an object with linear motion's displacement?
Definition
 Δx = v0t + 1/2at2
Term
 acceleration due to gravity (g)
Definition
 9.8 m/s2
Term
 projectile motion
Definition
 has vertical and horizontal components that are independent
Term
 If vx is constant then...
Definition
 ax = 0
Term
 How do you find a projectiles total time in flight?
Definition
 y = voyt + 1/2at2
Term
 How do you find a projectile's maximum height?
Definition
 Vy2 = V0y2 + 2ay
Term
 How do you find the horizontal distance travelled by a projectile?
Definition
 x = vxt
Term
 Force
Definition
 vector quantity observed as a push or a pull on an object
Term
 weight
Definition
 mass * gravity
Term
 Newton's first law of motion
Definition
 a body at rest or in motion with constant velocity will remain that way unless a force acts on it
Term
 Newton's second law of motion
Definition
 F = ma
Term
 Newton's third law of motion
Definition
 Objects always exert equal and opposite forces on each other
Term
 Gravity
Definition
 attractive force felt by all matter F = Gm1m2r2  G = 6.67 x 10-11
Term
 torque
Definition
 force that causes rotation Τ  = rFsinθ
Term
 What angle creates maximum torque? Minimum?
Definition
 max at 90°min at 0°
Term
 When is torque postitive? negative?
Definition
 counterclockwise motion creates positive torqueclockwise motion creates negative torque
Term
 Static friction (fs)
Definition
 force overcome to set an object in motion 0 ≤fs≤ μsN
Term
 Kinetic friction (fk)
Definition
 friction force during movement fk = μkN
Term
 centripetal acceleration
Definition
 radial component of acceleration a = v2/r
Term
 centripetal force
Definition
 gives rise to centripetal acceleration F = mv2/r
Term
 Work
Definition
 Work = force * distance W = fdcosθ
Term
 power
Definition
 work/time
Term
 kinetic energy (K, KE)
Definition
 energy of motion  1/2mv2
Term
 potential energy (U, PE)
Definition
 energy of position mgh
Term
 Is friction conservative?
Definition
 no; work lost in heat
Term
 conservation of energy
Definition
 Ei = Ef ΔE = 0
Term
 How do pulley's reduce work?
Definition
 reduce force necessary by increasing distance travelled
Term
 momentum (p)
Definition
 mass * velocity
Term
 impulse (J)
Definition
 product of force and the time it was applied J = Ft = Δp
Term
 inelastic collisions
Definition
 KEbefore > KEafter (lost to heat)
Term
 elastic collisions
Definition
 KE before = KE after
Term
 How do you convert temperatures?
Definition
 Tc = Tk - 273 Tf = 9/5Tc + 32
Term
 linear expansion
Definition
 increasing temperature causes an increase in length ΔL = αLΔT  α = coefficient of linear expansion
Term
 How is kinetic energy related to heat?
Definition
 heat transferred into a system causes an increase in kinetic energy
Term
 conduction
Definition
 direct transfer of energy from molecule to molecule via collisions
Term
 convection
Definition
 transfer of heat through mass motion of heated material
Term
Definition
 transfer of energy by electromagnetic waves
Term
 When is heat gained?
Definition
 q = mcΔT q>0 heat is gained
Term
 How do you determine heat gained or lost during a phase transition?
Definition
 q = mL L = heat of fusion, heat of vaporization
Term
 What creates gas pressure in a container?
Definition
 P = F/A pressure is created by gas molecules colliding with walls of container
Term
 Describe the work done by a gas on its surroundings
Definition
 positive workincreases volume
Term
 Describe the work done on a gas by its surroundings
Definition
 negative workdecreases volume
Term
 internal energy
Definition
 sum of all potential and kinetic energies of molecules in the system
Term
 change in internal energy (ΔU)
Definition
 Q - W
Term
 What does it mean when ΔU increases?
Definition
 Q increases or W decreases work is done on the system
Term
 What does it mean when ΔU decreases?
Definition
 Q decreases or W increases work done by the system
Term
Definition
 Q = 0 ΔU = -W
Term
 Constant volume
Definition
 W = 0 Δ = Q
Term
 Closed cycle
Definition
 ΔU = 0 Q = W
Term
 entropy
Definition
 measure of disorder within the system
Term
 second law of thermodynamics
Definition
 the universe tends toward disorder
Term
 entropy change in isothermal processes
Definition
 ΔS = Q/T
Term
 density
Definition
 mass/volume independent of size
Term
 specific gravity
Definition
 ratio of density of object to water
Term
 Absolute pressure
Definition
 p = p0 + Ρgh
Term
 Pascal's principle
Definition
 change in pressure is transmitted to every portion of the fluid F1d1 = F2d2
Term
 Archimede's principle
Definition
 body wholly or partially submerged in a fluid will be buoyed up by a force equal to the weight of the fluid it displaces
Term
Definition
 attractive force a molecule feels toward molecules of another substance
Term
 cohesion
Definition
 attractive force of same molecules within a liquid
Term
 Bernoulli's equation
Definition
 P1 + 1/2ρv12 + ρgy1 = P2 + 1/2ρv22 + ρgy2
Term
 What happens to velocity if cross section is decreased?
Definition
 increased
Term
 Viscosity
Definition
 measure of internal friction of fluid
Term
 moduli
Definition
 quantities that define a solid's ability to stretch
Term
 What kind of charges attract and repel?
Definition
 like charges repel, unlike charges attract
Term
 electrostatic force
Definition
 force between two stationary charges
Term
 coloumb's law
Definition
 magnitude of electrostatic force F = kq1q2/r2
Term
 electric field
Definition
 vector defined by a group of electric charges E = F/q0
Term
 Describe the force experienced by a charge in an electric field
Definition
 F = qE positive - force is in direction of the field negative - force is opposite direction of the field
Term
 Electric potential (V)
Definition
 work needed to move a positive test charge from infinity to that point V = W/q0  Work depends on potential difference and not the path taken
Term
 What creates a magnetic field?
Definition
 moving charges or a magnet
Term
 Describe the force on a charge in a magnetic field
Definition
 F = qvBsinθ
Term
 When is there no force on a charge in a magnetic field?
Definition
 When charge moves parallel or antiparallel to magnetic field
Term
 Describe the right hand rule.
Definition
 Palm faces in direction of forceFingers point in direction of fieldThumb points toward velocity
Term
 What happens when a charged particle moves perpendicular to a magnetic field?
Definition
 Has constant circular motion where centripetal force = magnetic force F = qvB = mv2/r
Term
 current
Definition
 direction in which positive charges would flow between two points with a potential difference
Term
 How is current related to the direction of electron flow?
Definition
 they are opposite (current direction describes flow of protons)
Term
 Describe force on a current carrying wire in a magnetic field.
Definition
 F = iLBsinθ
Term
 Force on wire with no current
Definition
 zero
Term
 magnetic field lines
Definition
 come out of north pole of magnet, go into south pole
Term
 magnetic field created by current carrying wire
Definition
 right thumb points in direction of currentfingers curl around wire to mimic circular direction of field B = μ0i       2∏r
Term
 conductors
Definition
 allow charges to move freely
Term
 insulators
Definition
 retard flow of electricity
Term
 current (i)
Definition
 amount of charge passing through a point over a given time interval
Term
 How does current flow?
Definition
 from high potential to low potential (positive to negative termini)
Term
 electromotive force (emf)
Definition
 voltage difference across terminals when no current is flowing
Term
 Ohm's law
Definition
 voltage drop across a resistor is proportional to current it carries V = iR
Term
 What does resistance depend on?
Definition
 length (R increases as L increases)cross sectional area (R decreases as A increases)temperature (R increases with temperature)
Term
 Resistivity
Definition
 intrinsic resistance to current flow
Term
 power
Definition
 energy/second
Term
 Kirchoff's law
Definition
 at any junction, sum of currents into the point equals sum of currents directed away from the point sum of voltage sources is equal to sum of voltage drops around a closed curcuit loop
Term
Definition
 increases resistance total current decreases
Term
Definition
 decreases resistance total current increases
Term
 capacitor
Definition
 two plate system connected to a voltage device that stores charge C = Q/V C = ε0A/d  (capacitance depends on geometry of plate)
Term
 Dielectric materials
Definition
 usually insulating material when added to a capacitor, decreases voltage so increases capacitance
Term
 capacitors in parallel
Definition
 can be added directly to increase total capacitance of combination
Term
 capacitors in series
Definition
 decrease total capacitance
Term
Definition
 Rs = R1 + R2 .... Rn 1/Cs = 1/C1 + 1/C2 .... 1/Cn
Term
Definition
 1/Rp = 1/R1 + 1/R2 .... 1/Rn Cp = C1 + C2 ... Cn
Term
 simple harmonic motion
Definition
 mass oscillates about an equilibrium point subject to a linear restoring force
Term
 characteristics of a linear restoring force
Definition
 1. always directed back towards equilibrium2. magnitude is proportional to displacement from the equilibrium position F = -kx
Term
 spring constant (k)
Definition
 larger k means stronger, stiffer spring
Term
 potential energy in a spring
Definition
 1/2 kx2
Term
 Describe potential and kinetic energy during simple harmonic motion
Definition
 U=0 and K=max at equilibrium point U=max and K=0 at maximum displacment
Term
 transverse waves
Definition
 particles oscillate perpendicular to direction of wave motion
Term
 longitudinal waves
Definition
 particles oscillate along the direction of the wave motion
Term
 How are frequency of period and waves related?
Definition
 reciprocals v =  fλ k=2∏/λ
Term
 phase difference
Definition
 crests of two waves don't occur at same point in space
Term
 constructive interference
Definition
 two waves in phase interact and amplitudes add
Term
 destructive interference
Definition
 waves interact out of phase
Term
 What can't sound travel through?
Definition
 vaccuum
Term
 What medium does sound travel fastest through?
Definition
 Solid - smaller spaces between particles allow soind to travel faster
Term
 Audible range for humans
Definition
 20 to 20,000 Hz
Term
 intensity
Definition
 power/area p=IA
Term
 sound level
Definition
 β = 10 log I/I0 I0 = 10-12 (hearing threshold)
Term
 beats
Definition
 heard when two waves with almost equal frequencies are superimposed
Term
 Doppler effect
Definition
 Source that emits sound and that detects sound move relative to one another so perceived frequency changes f' = f(v‡vdetect)       (v‡vsource)  v = speed of sound in medium
Term
 speed of light
Definition
 3 x 108
Term
 visible light range
Definition
 violet (400 nm) to red (700 nm)
Term
 reflection
Definition
 rebounging of incident light waves at the boundary of the medium
Term
 real image (mirror)
Definition
 light converges at image
Term
 virtual image (mirror)
Definition
 light appears to be coming from image but doesn't converge there
Term
 concave mirror
Definition
 converging positive focal length
Term
 convex mirror
Definition
 diverging mirror negative focal length
Term
 negative image distance
Definition
 image is behind mirror, virtual
Term
 In what is the speed of light fastest?
Definition
 vaccuum
Term
 Snell's law
Definition
 n1sinθ1 = n2sinθ2
Term
 What happens if light moves from a medium with low index of refraction to high index refraction?
Definition
 bends towards the normal
Term
 Critical angle
Definition
 refracted angle is 90° if angle is greater than the critical angle, total internal reflection occurs
Term
 Total internal reflection
Definition
 all incident light is reflected back into original material
Term
 How do you compare image and object distance in a lens?
Definition
 1/f = 1/do + 1/di
Term
 Rainbow in a prism
Definition
 visible light is split into component colors because each wavelength has a different index of refraction
Term
Definition
 all matter above absolute zero emits EMR
Term
 frequency  of light
Definition
 E = hv c = λv
Term
 photoelectric effect
Definition
 energy of emitted electron is the energy of the incident light minus work function of hte metal KE = hv - W W = hv0
Term
 absorption
Definition
 lower to higher energyyields color
Term
 emission
Definition
 higher to lower energyyields fluorescence
Term
 nucleons
Definition
 neutrons and protons
Term
 deuterium
Definition
 isotope of hydrogen with two neutrons
Term
 tritium
Definition
 isotope of hydrogen with 3 neutrons
Term
 mass defect
Definition
 mass of a nucleus is always less than the combined masses of its constituent protons and neutrons
Term
 Binding energy
Definition
 Holds nucleus togethercomes from mass defectBE = Δmc2
Term
 fusion
Definition
 combine smaller nuclei into larger nucleus
Term
 fission
Definition
 split larger nucleus into smaller nucleus
Term
 alpha decay
Definition
 Zdaughter = Zparent -2Adaughter = Aparent - 4
Term
 beta- decay
Definition
 A stays the sameZ+1 (ß- is electron)
Term
 beta+ decay
Definition
 A stays the sameZ-1 (ß+ = positron)
Term
 gamma decay
Definition
 high energy photons; release doesn't change A or Z
Term
 exponential decay
Definition
 n = n0e-λt n0 = number of undecayed nuclei at t=0
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