Fluids and Solids: Mechanics

Question 1

Equation: Mass Density

Answer 1

density (rho) = mass/ Volume = m / V

SI Unit: kg / m^3

Question 2

Density of liquid water

Answer 2

1000 kg / m^3

1 * 10^3 kg / m^3

Question 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

Answer 3

specific gravity

Question 4

Equation: Specific Gravity

Answer 4

S.G. = density of substance / density of liquid water 
S.G. = density of substance / (1000 kg / m^3)

Question 5

Force acting over a unit area

Answer 5

pressure

Question 6

Equation: Pressure

Answer 6

Pressure (P) = Force / Area = F / A

SI Unit = N / m^2 = Pascal (Pa)

Question 7

Equation: Fluid Pressure

Answer 7

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

Question 8

According to Pascal’s Law, when pressure is increased at any point in the contained fluid, the increase is distributed _______ through the fluid.

Answer 8

uniformly

Question 9

Equation: Total Pressure of open container

Answer 9

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

Question 10

The magnitude of the buoyant force is equal to the _______ of the fluid displaced

Answer 10

weight

Question 11

Equation: Buoyant Force: F(b)

Answer 11

F(b) = density of fluid * V * g
SI Unit = Newtons (N)
Note: V = submerged volume of the object

Question 12

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

Answer 12

Buoyant Force

Question 13

When determining how an object will behave in a fluid, compare the _______ of the two objects.

Answer 13

Densities

i.e. set up specific gravity ratio! Buoyant force does not describe how an object will behave in a fluid

Question 14

transverse waves that can travel through a vacuum

all move through a vacuum at the same speed (speed of light, c)

Answer 14

electromagnetic waves

Question 15

Speed of light / electromagnetic wave in a vacuum (c)

Answer 15

c = 3 * 10^8 m/s

Question 16

Equation: Velocity of an electromagnetic wave

Answer 16

v = frequency * wavelength
SI Unit = m / s
Note: f = frequency (Hz); wavelength in m

Question 17

type of wave on the electromagnetic spectrum
longest wavelength (700 nm)
lowest frequency
lowest energy
color = red

Answer 17

radio waves

Question 18

type of wave on the electromagnetic spectrum
shortest wavelength (400 nm)
highest frequency
highest energy
color = purple

Answer 18

gamma rays

Question 19

Order of electromagnetic waves in electromagnetic spectrum (shortest wavelength/highest f and E&raquo_space;» longest wavelength / lowest f and E)

Answer 19

gamma rays
x-rays
ultra-violet
visible
infrared
microwaves
radio waves

Question 20

area just outside the visible spectrum
slightly shorter wavelength
slightly higher frequency and E

Answer 20

ultraviolet waves

Question 21

area just outside the visit spectrum
slightly longer wavelength
slightly lower frequency and E

Answer 21

infrared waves

Question 22

Visible light increases in FREQUENCY (and energy, decreases in wavelength) in the order of ______

Answer 22

ROYGBIV

Question 23

wavelengths are often expressed in nanometers (nm), which =

Answer 23

1 nm = 10^-9 meters

Question 24

wavelengths are measured between ________ and ______.

Answer 24

crest and crest

trough and trough

Question 25

maximum displacement of an electromagnetic wave

Answer 25

amplitude

Question 26

electromagnetic wave that moves parallel to the direction of the propagation of the wave

Answer 26

longitudinal wave

Question 27

electromagnetic wave that moves perpendicular to the direction of the wave

Answer 27

transverse wave

Question 28

two waves of the same frequency can have different ________ and can be “in” or “out” of ___

Answer 28

phases

in phase or out of phase

Question 29

if the crest of one wave coincides with the crest of the other, then waves are said to be ________

Answer 29

in phase

Question 30

90º out of phase means that one wave is _____ wavelength ahead of the other one

Answer 30

1/4 wavelength

Question 31

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

Answer 31

1/2 wavelength

Question 32

360º out of phase means that one wave is ______ wavelength offset. This is the same as being “in phase”

Answer 32

one complete wavelength

Question 33

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

Answer 33

constructive interference

Question 34

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

Answer 34

destructive interference

Question 35

waves in which the positions of maximum and zero displacement are fixed

Answer 35

standing waves

Question 36

for a standing wave in a pipe with both sides open, the length of the pipe = ______

Answer 36

1/2 * wavelength

Question 37

What will occur if two waves are 1/2 of a wavelength out of phase?

Answer 37

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