MCAT Physics Flashcards
The center of mass of an object with a constant density is its__
geometric center
An object moving in a circular path is said to execute uniform circular motion if___
its speed is constant, NOT VELOCITY
A thermodynamic process in which there is no heat exchange
Adiabatic
What is the formula for angular momentum
Lmv
L = dstance, measured perpendicularly
m = mass
v = velocity
A completely inelastic collision is an inelastic collision in which the colliding objects stick together afterwards and thus have a single velocity after the collision
Completely inelastic collision
A mode of heat transfer in which the medium does not move during the transfer of thermal energy
Conduction
If the work done by a force depends only on the initial and final positions of the object that the force is acting on, and not on the particular path between the positions the force is a
Conservative force
Gravitational and electric force are__
conservative forces
A mode of heat transfer in which the medium moves during the transfer of thermal energy
Convection
The percentage of the useful work that a machine does in comparison to its theoretical maximum, or
Work(output) / Energy(input)
Efficiency
The product of force and time during which it acts
Impulse = Ft
Impulse
Thermodynamic process in which pressure is held constant
Isobaric
Thermodynamic process in which the volume is held constant
Isochoric
Thermodynamic process in which temperature is held constant
Isothermal
The SI unit of work and energy
Joule
momentum =
mass times velocity
The SI unit of force =
Newton 1 N = 1kg x m/s^2
Two objects in thermal equilibrium with the same third object are in thermal equilibrium with each other. Defines temperature as a state function
0th law of thermodynamics
The total quantity of energy in the universe is conserved. The energy into and out of a system equals its change in internal energy
change in E = Q - W
1st law of thermodynamics
The entropy of a closed system will either stay the same or increase
2nd law of thermodynamics
The SI unit of power
Watt 1 W = 1 joule per second 1 J/s
Formula for work
Work = Fd or Fdcos(theta)
The total amount of work done on an object is equal to the change in the object’s kinetic energy
W = change(K.E.)
Work-Energy theorem
Describes a thermodynamic process in which there is no heat exchange
Adiabatic
A mode of heat transfer in which the medium does not move during the transfer of thermal energy
Conduction
A mode of heat transfer in which the medium moves during the transfer of thermal energy
Convection
The magnitude of the buoyant force on an object is equal to the weight of the fluid displace. So if the density of the fluid is (Pfluid) and the volume of the object that is submerged is (Vsub), then the magnitude of the buoyant force is given by
Fbuoy = Pfluid x Vsub x gravity
Archimedes’ Principle
The lowering of fluid pressure as the flow speed increases; also known as the Venturi effect
Bernoulli effect
The statement that follows from the conservation of mechanical energy applied to ideal fluid flow
Bernoulli’s equation
The upward force exerted by a fluid on an object partly or completely submerged in it. If the density of the fluid is (Pfluid) and the volume of the object that is submerged is Vsub, then the magnitude of the buoyant force is given by (Fbuoy = Pfluid x Vsub x gravity)
Buoyant force
A type of stress applied to an object that decreases its length
Compression
For ideal fluid flow, the amount of fluid per unit time (the flow rate) passing one point in a flow tube must be the same as the amount passing through another point
f1 = f2
or
A1v1 = A2v2
Continuity equation
ThThe amount of fluid that flows per unit time; it is equal to the cross-sectional area of the flow tube multiplied by the flow speed F = Av
Flow rate
A substance that can flow, or more precisely, a substance that cannot withstand a shear stress. But liquids and gases are __
fluids
The pressure at a point below the surface of a fluid at rest, due to the weight of the fluid above it
Pgauge = Densityfluid x gravity x D (D is depth)
Hydrostatic gauge pressure
A confined fluid transmits an externally applied change in pressure to all parts of the fluid equally
Pascal’s Law
The magnitude of the shearing force exerted on an object divided by the area parallel to which it acts
Shear stress
The unitless ratio of the density of a substance to the density of water
Specific gravity
Density of substance/ Density of water
The magnitude of the force acting on an object, divided by the area over which it acts.
Stress
The equation of efflux for a static fluid from a small hole in a large open container:
v = root2gD where D is depth of the hole below the surface of the fluid
Torricelli’s result
The internal friction of a fluid; an ideal fluid is one whose __ is negligible
Viscosity
If density of an object is greater than the fluid it is in, the object___
will float, and the fraction of its volume that’s submerged is the same as the ratio of its density to the fluids density
If an object’s density is 3/4 the density of the fluid it is in, then___
3/4 of the object will be submerged
The force of surface tensions is
surface tension = F/2L
A confined fluid will transmit an externally applied pressure change to all parts of the fluid and the walls of the container without loss of magnitude.
Pascal’s Law
___ is the volume of fluid that passes a particular point per unit time, like how many liters of water per minute are coming out of the fauce.
Flow rate
Flow rate formula
f = Av A = cross-sectional area of pipe at any point v = speed of flow at that point
SI units are m^3/s
What are the four satisfactiosn necessary for an ideal fluid under Bernoulli’s Equation?
- The fluid is incompressible
- There is negligible viscosity
- Viscosity is the force of cohesion between molecules in a fluid; similar to internal friction for fluids - The flow is laminar
- when the flow is laminar, the fluid flows smoothly through the tube - The flow rate is steady
__ is a statement of conservation of total mechanical energy for ideal fluid flow
Bernoulli’s equation
Bernoulli’s effect tells us that the pressure is lower where__
the flow speed is greater
What are the three ways stress force can be applied to an object
- Tension (stretching) force
- Compression (squeezing) force
- Shear (bending) force
The formula for stress =
Stress = Force/Area
Unit of stress, similar to force is
N/m^2 or pascal (Pa)
A material with a very low resistivity, which therefore allows charge to flow through it easily. Metals are good__
conductors
The SI unit of charge, abbreviated C
Coulomb
The fundamental electric charge (the charge on a proton of the magnitude of the charge on an electron) is defined to be
e = 1.6 x 10^-19
1 Coulomb = 6.25 x10^18 protons
The law that gives the magnitude of the electric force between two charged objects
Coulombs Law
An insulating material sandwiched between the plates of a capacitor; a capacitor always has a higher capacitance when this is present
Dielectric
The force exerted by an electric field; if a charge (q) is in an electric field (E) then the electric force on q is given by the equation
F = qE
A curve or surface on which the electric potential remains constant
Equipotential
A material with a very high resistivity that does not permit charge to flow through it easily. Glass and wood are exampls
Insulator
The SI unit of electric potential and voltage
1 Volt (V) = 1 joule per coulomb = 1J/C
The difference in electric potential between two points =
Voltage
___ indicates the ease with which electrons flow within the molecular structure of a material
Conductivity
__is inversely proportional to a materials resistivity
Conductivity
__will form an inverted, real image when the reflected object is located outside of the focal length
Concave mirrors
___will form an upright virtual image when theo bject is placed inside the focal length
Concave mirror
The focal length of a ___ is positioned in front of the mirror
Concave mirror
__describes the phenomenon by which real lenses perfectly rounded surfaces do not produce an image at a single point but rather at a series of focal points
Spherical aberrations
To correct spherical aberrations of a converging lens, you must __
decrease the thickness of periphery lens to decrease the refraction of light
__describes the failure of a lens to focus multicolored light onto a single point
Chromatic dispersion
