Physics Flashcards
Displacement (s)
vector representing change in position
Velocity (v)
rate of change of displacement w/ respect to time
Acceleration (a)
rate of change of velocity w/ respect to time
Kinematics Equations
- used to describe motion under constant acceleration
Free Body Diagram
graphical representation showing all forces acting on an object to analyze dynamics
Newton’s 1st Law
- object at rest remains at rest & object in motion stays in motion at a constant velocity unless acted upon by a net external force
- law of inertia
Newton’s 2nd Law
F = ma
- law of acceleration
Newton’s 3rd Law
- for every action there is an equal and opposite reaction
- forces come in pairs
- law of interaction
Friction (f)
- resistive force that opposes relative motion of 2 surfaces in contact
- f= μN
- Coefficient of friction (μ)
Weight (W)
- force exerted on an object due to gravity
- W = mg
Momentum (p)
p = mv
Conservation of Momentum
in a closed system, total momentum remains constant if no external forces act on it
Work (W)
- energy transferred to/from an object via application of force along displacement
- W = Fdcos(θ)
Energy (E)
- capacity to do work
- Kinetic Energy: E = (1/2) mv^2
- Potential Energy: E = mgh
Power (P)
- P = w/t : rate at which work is done / energy is transfered
- P = IV : rate at which electrical energy is consumed or produced in a circuit
Fluid
- substance that can flow
- liquids & gases
- ability to deform under shear stress
Density (ρ)
ρ = m / V
Pressure (P)
P = F / A
Hydrostatic Pressure
- exerted by fluid at equilibrium due to weight of fluid above it
- P = ρgh
Bernoulli’s Equation
- conservation of energy in fluid flow
- P + (1/2) ρv^2 + ρgh = constant
Continuity Equation
- mass flow rate of a fluid must remain constant from one cross-section of a pipe to another
- A1v1 = A2v2
Viscosity (μ)
measure of fluid’s resistance to deformation/flow
Reynolds Number (Re)
- dimensionless number used to predict flow patterns in different fluid flow situations
- Re = (ρvL) / μ
Laminar FLow
- smooth, orderly flow characterized by parallel layers of fluid w. little to no disruption between tem
- typically low Re
Turbulent Flow
chaotic flow w/ irregular fluctuations and mixing
- high Re
Flow Rate (Q)
Q = Av
Drag Force (Fd)
- resistance force experience by an object moving thru a fluid
- depends on object’s speed, shape, and properties of fluid
Bernoulli’s Principle
increase in speed of fluid occurs simultaneously w/ decrease in pressure/potential energy
Stokes’ Law
- describes force of viscosity on a sphere moving thru a viscous fluid
- F = 6πμrv
Pascal’s Principle
change in pressure applied to incompressible fluid in a close container is transmitted undiminished throughout fluid
Buoyancy
- upward fore exerted by fluid on an object submerged in it
- opposed weight of object
- Archimedes’ Principle
Wave
- disturbance that transfers energy thru medium w/o transferring matter
- Mechanical / Electromagnetic
Wavelength (λ)
- distance between successive crests/troughs
- inversely proportional to frequency
Frequency (f)
number of wave cycles that pass a given point per unit time
Wave Speed (v)
** v = fλ**
Amplitude (A)
- maximum displacement of points on a wave from equilibrium position
- indicates wave’s energy
Transverse Wave
particle displacement is perpendicular to direction of wave propagation
Longitudinal Wave
particle displacement is parallel to direction of wave propagation
Reflection
- bouncing back of wave when it hits a barrier
- angle of incidence = angle of reflection
Refraction
- bending of waves as they pass from one medium to another due to a change in speed
- Snell’s Law
DIffraction
- spreading out of waves when they encounter an obstacle/aperture
- degree of spreading depends on wavelength & size of obstacle
Interference
- 2+ waves overlap & combine to form new wave pattern
- constructive (amplifying) / destructive (diminishing)
Standing Wave
- remains in constant position
- interference of 2 traveling waves moving in opposite directions
- nodes & antinodes
Doppler Effect
change in frequency / wavelength in relation to an observer moving relative to wave source
Harmonics
- integer multiples of fundamental frequency that determine pitches of vibrating system
- overtones
Gravity
- force of attraction between 2 masses
- governs motion of celestial bodies
- Newton’s law of universal gravitation
Gravitational Constant (G)
~ 6.674 x 10^(-11) N(m/kg)^2.
Acceleration due to Gravity (g)
- experienced by object in free fall
- Earth: ~9.81 m/s^2
Free Fall
- motion of an object under influence of only gravitational force w/o air resistance
- all in free fall fall at same rate regardless of mass
Orbital Motion
- curved path of an object around central body due to gravitational attraction
- Kepler’s Laws of Planetary Motion
Escape Velocity
- minimum velocity required for object to break free from gravicational attraction of planet/moon w/o further propulsion
- v_e = √(2GM/r)
Cavendish Experiment
- Henry Cavendish
- measure force of gravitational attraction between masses
- 1st accurate value of Gravitational Constant (G)
Electromagnetism
interaction between electric charges and magnetic fields
Coulomb’s Law
- electrostatic force between 2 charged objects
- F = k(q1q2)/r^2
Electric Field (E)
- region around charged object where other charged objects experience a force
- E = F/q
Magnetic Field (B)
vector field surrounding magnets / moving charges
Faraday’s Law of ELectromagnetic Induction
- change in magnetic flux thru circuit indues an elecromotive force (emf)
- emf = dΦ_B/dt
- magnetic flux: Φ_B
Lenz’s Law
- direction of induced current opposes change in magnectic flux that produced it
- consequence of conservation of energy
Ampere’s Law
- related integrated magnetic field around a closed loop to the electric current passing thru the loop
- Φ_B * dl = μ_0 I
Maxwell’s Equations
- set of 4 equations describing behavior and interactions of electric & magnetic fields
- foundational to classical electromagnetism
Electromagnetic Waves
- propagate thru space carrying electromagnetic radiation
- oscillating electric & magnetic fields
- travel at speed of light in a vacuum
Lorentz Force
- force experienced by a charged particle moving thru electric && magnetic field
- F = q(E + v × B)
Voltage (V)
- electrical potential difference between 2 points
- drives flow of electric current
Current (I)
rate of flow of electric charge in a circuit
Resistance (R)
- opposition to flow of current in a circuit
- depends on material, length, and cross-sectional area of conductor
Ohm’s Law
V = IR
Series Circuit
IT = I1 = I2
RT = R1 + R2
Parallel Circuit
VT = V1 = V2
1/RT = 1/R1 +1/R2
Capacitance (C)
- ability of component to store electric charge
- farads (F)
- capacitors store energy in electric field created between their plates
Inductance (L)
- property of circuit component that opposed changes in current
- henries (H)
- inductors store energy in magnetic field when current flows thru
Kirchhoff’s Voltage Law (KVL)
sum of voltage around closed loop in circuit
Kirchhoff’s Current Law (KCL)
total current entering junction equal total current leaving
Resistivity (ρ)
- quantifies how strongly material opposed flow of electric current
- R = ρ(L/A)
Equivalent resistance
total resistance
Capacitor Charge (Q)
- electric charge stored in capacitor
- Q = CV
Time Constant (τ)
time for voltage across capacitor to reach ~63.2% of final value when dis/charging
AC (Alternating Current)
- reverses direction periodically
- sinusoidal waveforms
- common in power distribution systems
DC (Direct Current)
- flows in 1 direction
- common in batteries and electronics
Impedance (Z)
- total opposition to current flow in AC circuit
- resistance & reactance
Reactance (X)
- opposition to current flow due to capacitance / inductance in AC circuit
- capacitive / inductive
RMS Voltage (V_ms)
- effective value of AC voltage that delivers same power to a resistor as a corresponding DC
- V_rms = V_peak / √2
Node
point in circuit w/ 2+ circuit elements connected
Loop
closed path in circuit thru current can flow
Ground
- reference poin in electrical circuit
- typically 0V
- common return path
Total Internal Reflection
when wave hits boundary at angle greater than critical angle causing it to be completely reflected back into original medium
Lens
- transparent optical device that refects light rays
- convergent: convex lens
- divergent: concave lens
Focal Length (f)
- distance between lens / mirror and focal point
- parallel rays of light converge / diverge
Lensmaker’s Equation
1/f = (n - 1)(1/R₁ - 1/R₂)
Magnification (M)
M = h’/h = - (d₁/d₂)
Mirror
- reflective surface that forms images
- plane, concave, convex
Spherical Aberration
distortion in spherical mirrors and lenses
Optical Fiber
thin, flexible strand of glass/plastice that transmits light thru total internal reflection
Young’s Double-Slit Experiment
demonstated wave nature of light, displaying interference patterns
Polarization
- orientation of oscillations of light waves in a particular direction
- polarizers can filter light to allow certain orientations to pass thru
Hyugens’ Principle
- each point on wavefront can be considered source of secondary wavelets which spread out in all directions
- wave propagation & diffraction
Critical Angle
- minimul angle at which total internal reflection occurs when light travels from a denser to rarer medium
- θ_c = sin⁻¹(n₂/n₁)
Spectroscopy
- study of interaction between light and matter
- to identify materials and analyze properties based on spectrum of light emitted / absorbed
Snell’s Law
n₁sin(θ₁) = n₂sin(θ₂)
Wavefront
surface over which oscillation has constant phase
Ray Diagram
show path of light rays for understanding image formation
Achromatic Lens
- designed to limit effects of schromatic & spherical aberration
- bring 2 wavelengths (typically blue & red) into focus on the same plane
Convex Lens
- bulges outward –> converge at focal point
- outside f: real inverted
- inside f: virtual upright
- farsightedness
Concave Lens
- curves inward –> spread apart
- always virtual upright reduced
- nearsightedness
Cylindrical Lens
- curvature in 1 direction –> focuses light into a line
- stretched along 1 axis
- astigmatism
Aspheric Lens
reduces spherical aberration
Concave Mirror
- curve inward –> converge at focal point
- outside f: real inverted
- inside f: virtual upright
Convex mirror
- bulges outward –> diverge
- always virtual upright reduced
