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66 Cards in this Set
- Front
- Back
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What is the velocity of an object if you only know its acceleration, ∆time and initial speed?
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v=vₒ+at
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What is the velocity of an object if you only know its acceleration, ∆time, and displacement?
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x=xₒ+vₒt+½at²
or v²=vₒ²+2a(x-xₒ) |
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What is force defined as?
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Mass (m) times acceleration (a)
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What is the force of friction always less than or equal to?
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µN
(coefficient of friction times the normal force) |
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What is the equation for centripetal acceleration?
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a= v²/r
r= radius of circle |
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What is the equation for torque?
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τ=rFsinθ
(torque = radius * force * sin theta) |
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What is the equation for momentum?
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p=mv
(momentum = mass * velocity) |
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What is the equation for impulse?
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J=F∆t=∆p
(impulse = force * time = change in momentum) |
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What is the equation for kinetic energy?
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KE=½mv²
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What is the formula for the potential energy of a falling object?
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∆Ug=mgh
(mass * gravity * height) |
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What is the equation for work?
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F*d*cosθ
(force times distance (distance can also be a radius) times cosine theta) |
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What is the equation for average/mean power?
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W/∆t
(work divided by time elapsed) |
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What is the equation for power (at a given instant)?
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P=Fv*cosθ
(power = force * velocity * cosine theta) |
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What equation can you use to fin d the spring constant?
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F=(-k)x
(force = negative spring constant * displacement) |
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What is the potential energy of a vertical spring?
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½kx²
(half of the spring constant times the displacement squared) |
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What is the period of a spring?
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2π√(m/k)
(2 pi times the square root of the mass (hanging) divided by the spring constant) |
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What is the period of a pendulum?
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2π√(l/g)
(2 pi times the square root of the length divided by gravity - mass is irrelevant) |
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What is the period equal to (in terms of frequency)?
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Its reciprocal. T=1/f
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What is the equation for the force of gravity acting in between two objects?
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-G(m1)(m2)/r²
(negtative) universal gravitational constant (G) times the first mass, times the second mass divided by the distance between the two objects squared |
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What is the gravitational potential energy between two objects?
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-G(m1)(m2)/r
(negative) universal gravational constant (G) times the first mass times the second mass divided by the distance between the two objects |
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What is the equation for electric force?
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F= 1/4πεₒ * (q1)(q2)/r²
(force equals one over 4 * pi * the vacuum permittivity constant, times the first charge * the second charge divided by the distance between the charges squared) |
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What is the equation for electric field?
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E=F/q
(electric field is equal to force divided by charge) |
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What is the potential energy of an electric field?
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UE=qV=F= 1/4πεₒ * (q1)(q2)/r
(potential energy = charge * voltage = force equals one over 4 * pi * the vacuum permittivity constant, times the first charge * the second charge divided by the distance between the charges) |
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What is the equation for finding the average electronic field?
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-V/d
((negative) voltage divided by distance) |
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What is the incredibly disgusting definition of voltage?
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V=1/4πεₒ Σ(qi/ri)
(voltage is equal to one over 4 * pi * the vacuum permittivity constant times all of the point charges' charge divided by all of the point charges' distance |
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What is the equation for capacitance?
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C=Q/V
(capacitance = charge / voltage) or εₒA --- d (vacuum permittivity constant * area divided by separation between two locations) |
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What is the equation for potential/stored energy in a capacitor?
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Uc=½QV=½CV²
(capacitor PE = one half time charge * voltage = one half times capacitance * voltage squared) |
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What is the equation for average current?
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∆Q/∆t
(change in charge divided by change in time) |
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What is the equation for resistance?*
*not used by Thor |
ρl/A
(resistance = resistivity * length divided by area) |
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What is voltage equal to?
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V=IR
(voltage = current * resistance) |
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What is power equal to (in electricity)?
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P=IV
(power = current times voltage) |
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How does one find the total capacitance of capacitors in parallel?
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Add them up and treat them as one capacitor (much like resistors in a series circuit)
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How does one find the total capacitance of capacitors in series?
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It is equal to the reciprocal of the sum all the reciprocals of the capacitors' capacitance
(confusing enough wording?) 1 1 1 -=-+-... C a b a and b being the capacitances of capacitors |
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How does one find the total resistance of resistors in a series circuit?
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Add them all up!
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How does one find the total resistance of resistors in parallel?
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It is equal to the reciprocal of the sum all the reciprocals of the resistors' resistance
(confusing enough wording?) 1 1 1 -=-+-... R a b a and b being the resistance of the resistors |
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What is the equation for the force of a magnetic field?
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FB=qvB*sinθ
(charge * velocity * magnetic field * sin theta) or FB=BIl*sinθ (magnetic field * current * length * sin theta) |
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What is the equation to find the magnetic field (in point charges)?
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µθ I
--*- 2π r (vacuum permittivity constant divided by 2 pi times current divided by distance) |
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What is the equation for magnetic flux?
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ϕ=BAcosθ
(magnetic field * area * cos theta) |
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What is the equation for average electromagnetic field (ε)?
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-∆ϕ
--- ∆t (the change in magnetic field divided by the change in time) |
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What is the equation for an electromagnetic field?
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ε=Blv
(magnetic field * length * velocity) |
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What is the equation for pressure?*
*Thor didn't use this much at all |
P=Pₒ+ρgh
(pressure = initial pressure + density * gravity * height) |
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What is the equation for buoyancy?
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Fbuoy=ρVg
(pressure * volume * gravity) |
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What's the relationship between two areas and volumes of a liquid?
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(A1)(V1)=(A2)(V2)
(area 1 * volume 1 = area 2 * volume 2) |
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What is a constant you can form from a gas pressure?
(this question sucks, sorry) |
P+ρgy+½ρv² = a constant
(pressure + density * gravity * height + one half of the density times velocity squared) |
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What is the equation for the change in length of an object (while it's heating up/cooling)?
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∆l=alₒ∆T
(change in length = coefficient of linear expansion times the initial length times the change in temperature) |
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What is the equation for the rate of heat transfer?
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kA∆T
---- L (thermal conductivity times area times change in time divided by thickness) |
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What is the equation for pressure?
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P=F/A
(pressure = force / area) |
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What is the universal gas equation?
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PV=nRT=N(Kb)T
(pressure * volume = number of moles * universal gas constant * temperature)= number of molecules * boltzmann's constant * temperature) |
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What is the equation for average molecular kinetic energy?
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K=(3/2)(Kb)T
(average molecular kinetic energy = 1.5 * boltzmann's constant * the temperature) |
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What is the equation for the root-mean-square velocity (in thermal physics)?
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Vrms=√(3RT/M)=√(3(Kb)T/µ)
(square root of 3 * the universal gas constant * the temperature divided by molar mass = the square root of 3 times boltzmann's constant * the temperature divided by the mass of the molecule) |
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What is the equation for work done on a thermal system?
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W=-P∆V
(work = negative pressure times change in volume) |
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What is the equation for the change of internal energy of a thermal system?
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∆U=Q+W
(change in thermal energy = heat transferred to the system + work done on the system) |
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What is the equation for efficiency (of heat engines and the like)?
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e=abs(W/(Qh))
(efficiency = the absolute value of the work done on the system divided by the heat transferred to the system) |
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What is the efficiency of a Carnot heat engine?
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Th-Tc
----- Th (hot temp - cold temp / hot temp) |
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What is the velocity of a wave?
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v=λ
(velocity = frequency * wavelength) |
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What is the equation for the index of refraction of a substance?
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n=c/v
(index of refraction = speed of light in a vacuum / speed of light in the substance) |
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What is the equation/guideline for the refraction of light?
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(n1)sinθ1=(n2)sinθ2
(the index of refraction of the first substance times the sine of the angle (to the normal) = the index of refraction of the second substance times the sine of the second angle (to the normal) |
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What is the equation for the critical angle of a substance?
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sinθ=n2/n1 (n1>n2)
(the sine of the critical angle is equal to the first index of refraction of a substance divided by the second) |
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What is the equation for a focal length?
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1 1 1
-=--+-- f do di (the reciprocal of the focal length is equal to the reciprocal of the object distance + the reciprocal of the image distance (don't forget to take the reciprocal of 1/do + 1/di when you're done adding them!) or f=R/2 (focal length = radius (of curvature)/2) |
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What is the formula for the magnification of an object?
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hi -si
--=-- hₒ sₒ (magnification = height of image divided by height of object or distance of image to lens from object to lens) |
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What is the equation for double-slit interference?
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dsinθ=mλ
(separation between slits * sine of the angle = maxima # or an integer * wavelength) |
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What is the equation for the separation between maxima?
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mλL
--- d (an integer or maxima # * wavelength * distance divided by separation) |
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What is the equation for energy of a particle?
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E=hf=pc
(energy = planck's constant * frequency = momentum * speed of light in a vacuum) |
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What is the maximum kinetic energy of a particle?
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Kmax=hf-ϕ
(max KE = planck's constant * frequency - work function) |
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What is the wavelength of a particle?
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λ=h/p
(wavelength = planck's constant / momentum) |
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What is the equation for the change in energy of a particle?
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∆E=(∆m)c²
(change in energy = change in mass * the speed of light in a vacuum squared) |
