Fluids and Solids: Mechanics Flashcards
Equation: Mass Density
density (rho) = mass/ Volume = m / V
SI Unit: kg / m^3
Density of liquid water
1000 kg / m^3
1 * 10^3 kg / m^3
ratio of the density of a substance to the density of liquid water
use to figure out what percent of a substance will float above water
object will sink if this value is > 1
object will float if this value is
specific gravity
Equation: Specific Gravity
S.G. = density of substance / density of liquid water S.G. = density of substance / (1000 kg / m^3)
Force acting over a unit area
pressure
Equation: Pressure
Pressure (P) = Force / Area = F / A
SI Unit = N / m^2 = Pascal (Pa)
Equation: Fluid Pressure
P = density * g * y
SI Unit = N / m^2 = Pascal (Pa)
Note: d = density of the fluid; g = 10 m/s^2; y = depth below the surface
According to Pascal’s Law, when pressure is increased at any point in the contained fluid, the increase is distributed _______ through the fluid.
uniformly
Equation: Total Pressure of open container
P(t) = P (fluid) + P (atm)
SI Unit = N / m^2 = Pascal (Pa)
Note: If container is open to the atmosphere, the atmospheric pressure must be considered
The magnitude of the buoyant force is equal to the _______ of the fluid displaced
weight
Equation: Buoyant Force: F(b)
F(b) = density of fluid * V * g
SI Unit = Newtons (N)
Note: V = submerged volume of the object
the strong upward force that a fluid applies to any object that is partially or completely immersed in it
equals weight of the fluid displaced
Buoyant Force
When determining how an object will behave in a fluid, compare the _______ of the two objects.
Densities
i.e. set up specific gravity ratio! Buoyant force does not describe how an object will behave in a fluid
transverse waves that can travel through a vacuum
all move through a vacuum at the same speed (speed of light, c)
electromagnetic waves
Speed of light / electromagnetic wave in a vacuum (c)
c = 3 * 10^8 m/s
Equation: Velocity of an electromagnetic wave
v = frequency * wavelength
SI Unit = m / s
Note: f = frequency (Hz); wavelength in m
type of wave on the electromagnetic spectrum longest wavelength (700 nm) lowest frequency lowest energy color = red
radio waves
type of wave on the electromagnetic spectrum shortest wavelength (400 nm) highest frequency highest energy color = purple
gamma rays
Order of electromagnetic waves in electromagnetic spectrum (shortest wavelength/highest f and E»_space;» longest wavelength / lowest f and E)
gamma rays x-rays ultra-violet visible infrared microwaves radio waves
area just outside the visible spectrum
slightly shorter wavelength
slightly higher frequency and E
ultraviolet waves
area just outside the visit spectrum
slightly longer wavelength
slightly lower frequency and E
infrared waves
Visible light increases in FREQUENCY (and energy, decreases in wavelength) in the order of ______
ROYGBIV
wavelengths are often expressed in nanometers (nm), which =
1 nm = 10^-9 meters
wavelengths are measured between ________ and ______.
crest and crest
trough and trough
maximum displacement of an electromagnetic wave
amplitude
electromagnetic wave that moves parallel to the direction of the propagation of the wave
longitudinal wave
electromagnetic wave that moves perpendicular to the direction of the wave
transverse wave
two waves of the same frequency can have different ________ and can be “in” or “out” of ___
phases
in phase or out of phase
if the crest of one wave coincides with the crest of the other, then waves are said to be ________
in phase
90º out of phase means that one wave is _____ wavelength ahead of the other one
1/4 wavelength
180º out of phase means that one wave is _____ of a wavelength ahead of the other
i.e. a crest of one wave meets with the trough of the other
1/2 wavelength
360º out of phase means that one wave is ______ wavelength offset. This is the same as being “in phase”
one complete wavelength
waves that are in phase experience this type of interference
two crests meet at the same point in space
the amplitude of the resulting wave is the sum of the individual amplitudes
constructive interference
a crest of one wave and a trough of another meet at the same point in space; the amplitude of the resulting wave is the difference of individual amplitudes
complete __________ is when the amplitudes are equal and 180º out of phase
destructive interference
waves in which the positions of maximum and zero displacement are fixed
standing waves
for a standing wave in a pipe with both sides open, the length of the pipe = ______
1/2 * wavelength
What will occur if two waves are 1/2 of a wavelength out of phase?
Destructive interference
Note: At the point in space at which one wave has a peak, the other will have a trough. If the two waves are 180º out of phase, they will show destructive interference
