Kaplan Math and Physics Unknown Concepts Flashcards
What are the vector quantities? Scalar?
vector: displacement, velocity, acceleration, force
- cross product results in vector
- AB * sine(theta)
- RHR determines direction of resultant vector
scalar: speed
- dot product results in scalar
- AB * cos(theta)
What is the difference between mass and weight?
mass: amount of material
weight: force experienced by a given mass due to its gravitational attraction to earth
What are Newton’s Laws?
object will remain at rest or move with a constant velocity if there is no net force on the object
any acceleration is the result of the sum of the forces acting on the object and its mass
any two objects interacting with one another experience equal and opposite forces
What is the total mechanical energy of a system?
KE + PE (gravitational, elastic, electrical, chemical)
What are conservative forces?
path independent and do not dissipate the mechanical energy of a system
- gravity, electrostatic forces
What are nonconservative forces?
path dependent and cause dissipation of mechanical energy as thermal or chemical energy
- friction, air resistance, and viscous drag
What is work?
process by which energy is transferred from one system to another
- area under PV curve
What is power?
rate at which work is done or energy is transferred
What is the work-energy theorem?
when net work is done on or by a system, the system’s KE will change
What is mechanical advantage?
factor by which a simple machine multiplies the input force to accomplish work
- inclined plane, wedge, wheel and axle, lever, pulley, screw
What is load? what is effort?
output force of a simple machine, which acts over a load distance
input force of a simple machine
What is efficiency?
ratio of machine’s work output to work input when nonconservative forces are taken into account
What is the zeroth law of thermodynamics?
objects are in thermal equilibrium when they are at the same temperature
- no net exchange of heat energy
heat is the process of energy transfer between two objects at different temperatures until they are at thermal equilibrium
What are state functions? process functions?
state: pathway independent and are not defined by a process
- pressure, density, temperature, volume, enthalpy, internal energy, entropy, Gibbs free energy
process: pathway from one equilibrium state to another
- work, heat
What is the first law of thermodynamics?
conservation of energy: total energy can never increase or decrease
What is the second law of thermodynamics?
in a closed system, energy will spontaneously and irreversibly go from being localized to being spread
- entropy = measure of how much energy has been spread out
What is conduction, convection, and radiation?
conduction: direct transfer of energy from molecule to molecule through molecular collisions
convection: transfer of heat by the physical motion of fluid over a material
- liquids and gases
radiation: transfer of energy between electromagnetic waves
What are the phase changes?
solid to liquid: fusion, melting
- melting point; heat of fusion
liquid to gas: boiling, evaporation, vaporization
- boiling point
solid to gas: sublimation
gas to liquid: condensation
liquid to solid: freezing or solidification
gas to solid: deposition
What is the difference between gas and liquid if they’re both fluids?
liquids retain their shapes regardless of their containers and are incompressible
gasses are compressible and take the shape of their containers
What is pressure?
measure of force per unit area; exerted by fluid on the walls of a container and on objects placed in a fluid
- scalar quantity
P = F/A
What is absolute pressure? absolute hydrostatic pressure?
sum of all pressures at a certain point within a fluid
- equal to the pressure at the surface of the fluid plus the pressure due to the fluid itself
P = P0 + pgz
What is gauge pressure?
difference between absolute pressure and atmospheric pressure
- in liquids, caused by the weight of the liquid above the point of measurement
P = P0 + pgz - Patm
What is Pascal’s principle?
pressure applied to an incompressible fluid will be distributed undiminished throughout the entire volume of fluid
P = F1/A1 = F2/A2
- hydraulics
V = A1d1 = A2d2
W = F1d1 = F2d2
What is buoyant force?
when an object is placed in a fluid, the fluid generates a buoyant force against the object that is equal to the weight of the fluid displaced by the object
- opposite direction of gravity
- if the buoyant force is larger than gravity, it will float and average density of object < average density of fluid