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1 BTU: the heat needed to raise the temperature of 1 pound of water by 1 degree F
Acceleration: change in velocity / time
Acceleration due to gravity on the earth: -10 m/s^2
amplitude: maximum displacement from equilibrium
Aristotle: believed that the natural state of objects was to be at rest
atmospheric pressure (atm): 100,000 n/m^2
azX: z+n
bernoulli’s equation: fluid flow velocity=u, fluid density=p (rho), fluid pressure=P P + ½ p x u^2 + p x g x h= constant
Brahe: Compiled the first detailed observational data on planetary motion (mars), without a telescope.
Buoyant force: weight of displaced water=volume of displaced water in liters x 10 n / liter
c=3x10^8 m/s: ?
Center of gravity (CG): the center of an object
Centripedal acceleration=: velocity squared / radius
Change in internal energy: heat into system – work done by system
Condition for stability: if the CG is above the edge, the object will not fall
Conduction: heat is transferred directly through a material with no bulk movement of material
Conservation of energy: you can’t get more work out than the energy you put in
continuity: v x A= constant
Convection: heat is carried from place to place by the bulk movement of either liquids or gasses
Convert Celsius to Fahrenheit: 9/5T(C)+32
Convert Celsius to Kelven: T(C) +273
Convert Fahrenheit to Celsius: 5/9 [T(F)-32]
definition of Bernoulii’s equation: as the speed of a moving fluid increases, the pressure within the fluid decreases
density of air: 1.25 kg/m^3
density of aluminum: 2,700 kg/m^3
density of lead: 11,000 kg/m^3
density of water: 1,000 kg/m^3
Distance traveled: ½ acceleration x time^2
Einstein: shows in 1905 that newtons laws were not valid for objects moving with speeds near the speed of light.
Emissive: the efficiency with which an object emits thermal radiation. Is a number between 0 and 1. A good emitter has an e close to 1.
Energy of motion (kinetic energy): ½ m v^2
Engine efficiency: work done / heat in
Engine efficiency cannot be 100%: you cant get as much out as you put in
entropy: the total disorder of an object
Equilibrium: net force=0 net torque=0
First Law of thermodynamics: If energy is transferred and the internal energy of system B decreases by some amount then the internal energy of system A must incrase by the same amount.
Flow through a pipe: π(P2-P1)D^4/128Ln n=fluid’s viscosity
Fluid force: pressure x area
Frequency: 1 / period (time)
frequency of light: speed of light / wavelength
Galileo: the first to do experimental studies of the laws of motion and was Imprisoned by Pope Urban VIII in 1633 for advocating the Copernican theory, also know as the heliocentric theory, that the earth was a planet revolving around the sun.
Heat: the energy that flows from one system to another because of their temperature difference.
Heat: mass x specific heat x temperature change
Heat capacity (specific heat): the amount of heat that is required to raise the temperature of one g of a substance by 1 degree C.
Heat capacity equation: heat Q= mass of sample x specific heat x temp change
incoming and outgoing flow rate formula: v1 x A1=v2 x A2
infrasound: sounds below 30 Hz
Internal energy: the sum of the energy of all the molecules in the system
Kepler: analized brahe’s data and verified the heliocentric theory. These regularities are known as Helpers Laws of Planetary motion.
law of conservation of energy: the change in internal energy= the heat absorbed- the work done
mass flow rate formula: p x u x A
measure of density: kg/m^3
measurement of pressure: Pascal (Pa) or pounds per square inch (psi)
mechanical wave: a disturbance that propagates through a medium
Mechanics: why things move
Momentum: mass x velocity
Net force: the total force (positive and negative) acting upon an object
Net force=0 net torque≠0: rod with forces applied at opposite ends in opposite directions
Net force≠0 net torque=0: rod with forces applied at opposite ends in the same direction
Newton: wrote Principia in 1687. Made the 3 laws of mechanics and law of gravity. He also invented calculus.
Newton’s Second Law: f=mass x acceleration
order of states of matter stronger to lesser forces between atoms: solids, liquids, gases
Period: time required to complete one cycle
period of a pendulum T of length L: 2π x square root L/g
period p of a mass m oscillating on a horizontal spring of force constant k: t=2π square root m/k frequency= square root k/m;/2π
Photon energy: hf
Physics: The study of how objects behave (from the very tiny to the very big, and from the beginning of the Universe to its ultimate fate).
Power (watts): current x voltage energy/time (joules per second)
Present velocity: initial velocity = acceleration x time
pressure at depth h: p + density x g h
pressure depends on: number density x temperature
pressure does what when depth is increased: it increases
Pressure=: force per unit area
Projectile: an object that is thrown or struck or shot and then travels under the influence of gravity
Quantum mechanics: new theory that explained behavior at the atomic level
Radiation: the heat transfer by electromagnetic waves – thermal light waves
Resistance: voltage / current
restoring force: the force that brings a system back to equilibrium
Rotational inertia (moment of inertia): how much torque it takes to get an object rotating
Second law of thermodynamics: if the temperature of system A is less then the temperature of system B then heat flows from B to A (hot to cold)
Speed of light: 18600 miles/sec
Stable: not easy to knock over
Stable structures: are wider at the base (which lowers their center of gravity)
static fluid formula: Fbottom=Ftop+mg where mg is the weight of the volume
the pressure of liquids _____ when it goes faster: decreases
The US uses how much of the total world energy consumption?: 25%
Thermal conductivity: the effectiveness of a material in conducting heat
Thermal radiation: T^4
Thermodynamics: the study of heat and its transformation into mechanical energy
Time for an object thrown to reach maximum height: time= the square root of 2 x height / acceleration due to gravity
Torque: the combination of force and point of application
Torque: force x lever arm
Total momentum before collision: equals total momentum after collision
ultrasound: sounds above 20,000 Hz
variation of pressure with depth: Fbottom-Ftop=mg=(density x vol) x g
Velocity required for an object to reach height h: initial velocity= the square root of 2gh
velocity through a medium: c/n
Velocity=: distance traveled / time
viscosity: a tendency for liquids to resist flowing.
Voltage: current x resistance
volume fluid flow rate: gallons per minute (gpm), liters/s, cubic feet per minute (cfm) or m^3/s
volume fluid flow rate formula: tube cross section area A, flow speed u vfr= u x A (m/s x m^2)
wave: a disturbance that moves through something
Wave speed=: wavelength x frequency
wavelength: length of a wave
Wavelength: c / f
Weight: mass x gravity
when ice in water melts what happens?: the level stays the same
Why does something move?: because nothing stops it