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speed
distance travelled per unit time
scalar
quantity described by magnitude but not direction (time, area, volume)
displacement
distance and direction of an object's change in position from the starting point
acceleration
(physics) a rate of change of velocity
velocity
a measure of both the speed and direction of a moving object. V=∆x/∆t
Ohm's Law
RESISTANCE=VOLTAGE/CURRENT. V = I•R
Density
mass per unit of volume.ρ=m/V(unit : kg /m3 )
Friction
the resistance encountered when one body is moved in contact with another. FF = μ•FN
Torque
"rotational equivalent of force"; a force applied so as to cause an angular acceleration. τ = F•L•sin θ
Newton's Second Law
The acceleration produced by a net force on a body is directly proportional to the magntude of the net force, is in the same direction as the net force, and is inversely proportional to the mass of the body. Fnet = ΣFExt = m•a
rotational equilibrium
sum of all torques acting on an object is zero. No net angular acceleration.
Angular frequency
ω. equal to √(k/m) or , 2(pi)(f)
Anti node
The point of maximum displacement in a standing wave.
Beats
Periodic frequency resulting from the superposition of two waves that have slightly different frequencies. f(beat) = |f₁-f₂|
Constructive interference
Addition of two waves when the crest of one overlaps the crest of another, so that their individual effects add together. The result is a wave of increased amplitude.
Destructive interference
interference in which individual displacements on opposite sides of the equilibrium position are added together to form the resultant wave. Must 180 degrees out of phase
Doppler effect
change in the apparent frequency of a wave as observer and source move toward or away from each other. Toward Away.
Simple Pendulum
a hypothetical pendulum suspended by a weightless frictionless thread of constant length. f = 1/ T and T=2π(sqrt L/g)
Sinusoidal motion
Back and forth oscillatory motion corresponding to sound. x = A•cos(ω•t) = A•cos(2•π•f •t) ω = angular frequency f = frequency
2nd Law of Thermodynamics
The principle whereby every energy transfer or transformation increases the entropy of the universe. Ordered forms of energy are at least partly converted to heat, and in spontaneous reactions, the free energy of the system also decreases. ΔU = QAdded + WDone On - Qlost - WDone By
Force caused by a magnetic field on a moving charge
F = q•v•B•sin θ
Potential Energy stored in a Capacitor
P = ½•C•V² An electronic device that can maintain an electrical charge for a period of time and is used to smooth out the flow of electrical current. Capacitors are often found in computer power supplies.
Magnetic Flux
Φ = B•A•cos θ
Heating a Solid, Liquid or Gas
Q = m•c•ΔT (no phase changes!) Q = the heat added c = specific heat. ΔT = temperature change, K
Friction
FF = μ•FN, the force that opposes the motion of one surface as it moves across another surface
Linear Momentum
An object's mass times its velocity. Measures the amount of motion in a straight line. momentum = p = m•v = mass • velocity momentum is conserved in collisions
Center of Mass - point masses on a line
xcm = Σ(mx) / Mtotal
Angular Speed vs. Linear Speed
Linear speed = v = r•ω = r • angular speed
Pressure under Water
P = ρ•g•h h = depth of water ρ = density of water
Universal Gravitation
F=g(m1m2/r^2) G = 6.67 E-11 N m² / kg²
Mechanical Energy
PEGrav = P = m•g•h KELinear = K = ½•m•v²
Impulse = Change in Momentum
F•Δt = Δ(m•v)
Snell's Law
n1•sin θ1 = n2•sin θ2
Index of Refraction
n = c / v c = speed of light = 3 E+8 m/s
Ideal Gas Law
P•V = n•R•T n = # of moles of gas R = gas law constant = 8.31 J / K mole., law that states the math relationship of pressure (P), volume (V), temperature (T), the gas constant (R), and the number of moles of a gas (n); PV=nRT.
Periodic Waves
v = f •λ f = 1 / T T = period of wave
Constant-Acceleration Circular Motion
ω = ωο + α•t θ θ−θο= ωο•t + ½•α•t² ω ω2 = ωο 2 + 2•α•(θ−θο) t θ−θο = ½•(ωο + ω)•t α θ−θο = ω•t - ½•α•t² ωο
Constant-Acceleration Linear Motion
v = vο + a•t x (x-xο) = vο•t + ½•a•t² v v ² = vο² + 2•a• (x - xο) t (x-xο) = ½•( vο + v) •t a (x-xο) = v•t - ½•a•t² vο
Density
mass/volume p= m/V
Torque
a force that causes rotation. τ = F•L•sin θ Where θ is the angle between F and L; unit: Nm
Newton's Second Law
Force equals mass times acceleration. Fnet = ΣFExt = m•a
Work
(physics) a manifestation of energy F•D•cos θ Where D is the distance moved and θ is the angle between F and the direction of motion, unit : J
Buoyant Force - Buoyancy
FB = ρ•V•g = mDisplaced fluid•g = weightDisplaced fluid ρ = density of the fluid V = volume of fluid displaced
Ohm's Law
V = I•R V = voltage applied I = current R = resistance
Resistance of a Wire
R = ρ•L / Ax ρ = resistivity of wire material L = length of the wire Ax = cross-sectional area of the wire
Hooke's Law
F = k•x Potential Energy of a spring W = ½•k•x² = Work done on spring
Electric Power
P = I²•R = V ² / R = I•V
Speed of a Wave on a String
T=mv^2/L
Projectile Motion
Horizontal: x-xο= vο•t + 0 Vertical: y-yο = vο•t + ½•a•t²
Centripetal Force
F=mv^2/R=mωr
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