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dmt > Basic Dive Physics > Flashcards

Basic Dive Physics Flashcards

1
Q

General Gas Law

A

Boyle, Charles and Gay-Lussac demonstrated that T,V, and P affect a gas in such a way that a change in one factor must be balanced by corresponding change in one or both of the others.

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2
Q

Boyle’s Law

A

@ a constant T, the absolute P and V of gas are inversely proportional.

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3
Q

Charles/Gay-Lussac Law

A

@ a constant P, the V of a gas is directly proportional to the change in absolute T.

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4
Q

Dalton’s Law

A

The total P exerted by a mixture of gases is equal to the sum of the P’s of each of the different gases making up the mixture, c/ each gas acting as if it alone was present and occupied the total V.

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5
Q

Henry’s Law

A

The amount of any given gas that will dissolve in a liquid @ a given T is directly proportional to the pp of that gas.

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6
Q

Archimede’s Principle

A

Any object wholly or partly immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object.

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7
Q

Kinetic Theory of gases

A

The kinetic energy of any gas @ a given T is the same as the kinetic energy of any other gas @ the same T.

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8
Q

SPAM

A

Squeezes
POIS
Air consumption
MMP - the amount of pressure your manifold compensates to allow comfortable breathing @ depth (overcoming the ambient pressure).

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9
Q

Partial Pressure:

The ____ is equal to the ____.

A

whole

sum

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10
Q

Partial Pressure relates to diving (2)

A

Gas toxicity (N2 narcosis and O2 to)

Re ‘C’ ops, determines TT’s

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11
Q

Natural factors that affect Buoyancy (4)

A

Air in lungs
Bone structure
Obesity
Leaness

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12
Q

Factors a diver can change to affect buoyancy (5)

A 
add/remove weight
put air in BC/LP
put air in dry suit
put air in lungs
thickness of wetsuit
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13
Q

Pressure results in 2 factors

A
  • hydrostatic pressure (wt of H2O)
  • atmospheric pressure (wt of Atmosphere)

*the human body must maintain pressure balance because it can only fx correctly c/ little pressure difference between the body and the outside world.

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14
Q

Measurements of Pressure (4)

A
  • Atm pressure = 14.7 psi
  • gauge pressure = the difference between the Atm and the pressure being measured.
  • ambient pressure = Atm + hydrostatic pressure.
  • absolute pressure = total pressure exerted (gauge + Atm).
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15
Q 
Numbers and Formulas:
   - ? wt of Atm = ?Atm = ? few = ? Ata
Formulas:
   - psig
   - D to Ata
   - psig to Ata
   - Ata to pp of gas
A
  • 14.7 psi = 1 Atm = 0 fsw = 1 Ata
  • D x .445
  • (D + 33) / 33
  • (D + 14.7) / 14.7
  • Ata x gas %
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16
Q

Wt of H20:

  • Seawater
  • Fresh water
A
  • 64lbs

- 62.4 lbs

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17
Q

O2 properties (4)

A

21% of air
metabolized in the body
the only gas the body uses
can be toxic @ Ata 1.3-1.6 or greater.

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18
Q

N2 Properties (4)

A

79% of air
used to dilute O2
inert gas
cause N2 Narcosis

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19
Q

Inert Gas

A

Gas not metabolized by the body but dissolves in the tissue.

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20
Q

CO2

A

byproduct of respiration or metabolized O2.

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21
Q

CO

A

byproduct of incomplete combustion.

22
Q

Humidity/Condensation:

  • causes…
  • how it affects dive equipment?
A
  • discomfort to the diver (moisten tissues)

- can freeze and/or block passages, fog or corrode equipment.

23
Q

Most dangerous change in pressure occurs between ___ Ata’s and ___ Ata’s.

A

1 and 2

24
Q

CAR acronym

A

Charging bottles
Air and stowage
Re ‘C’ ops

25
Q

Henry’s Law:

Factors that affect gas absorption (3)

A

depth, time, and condition of the body.

26
Q

Henry’s Law:

Conditions of the body (3)

A
  • gas T, decrease T then increases solubility.
  • body T, decrease T then body vasoconstricts inhibiting off gasing.
  • adipose tissue, holds 5x’s more inert gas (than water tissues) therefore takes longer to off gas.
27
Q

Gas diffusion

A

The intermingling of/or mixing of gas molecules.

28
Q

Energy in diving (3)

A

Light
Mechanical
Heat

29
Q

Light:

  • objects appear?
  • light travels ___ in H2O than in air?
  • color dissipates in what order?
  • is affected by?
A
  • closer
  • faster
  • ROYGBIV
  • salinity, turbidity, size of particles, and pollution.
30
Q

Mechanical (sound):

  • ____ water is more dense.
  • travels ___x’s faster in water because of increased ____.
A
  • cold
  • 4xs
  • therefore more difficult to determine where sound is coming from.
31
Q

Heat:

- Water is a better conductor of heat than air therefore @\_\_\_ deg F a diver loses heat faster than his body can replace it.    - heat in water is lost \_\_\_ x's faster then in air.    - a chilled diver is more susceptible to \_\_\_.
A
  • 70 deg F
  • 25
  • DCS
32
Q

Deviation from ‘D’ schedules may be done c/ (2)

A

recommendation of the DMO and concurrence of the CO.

33
Q

Deviation from ‘D’ schedules is done only…

A

in emergencies.

34
Q

When conducting SCUBA ops, the diver’s ___ is considered error free.

A

depth gauge.

35
Q

Delay :01 then

A

add the delay to the 1st ‘D’ stop

* disregard delays between stops.

36
Q

SCUBA ‘D’ dives can only be done when necessary c/ the authorization of the ___ or ___.

A

CO or OIC.

37
Q

Unlimited BT c/ dives less than or equal to ___ fsw.

A

20 fsw

38
Q

Ideally perform you deepest dives…

A

first.

39
Q

Disregard delays…

A

< :01.

40
Q

Delays >50’ and >:01 then

A

round the delay up & add to BT then recompute T/S and decompress accordingly.

  • Never change the LB time when charting.
41
Q

If the SI is ___, add multiple dive BT’s together and T/S for the deepest depth.

A

<:10

42
Q

Charting is a ____ document.

A

legal.

43
Q

RNT define.

A

Residual N2 Time - the left over N2 in the divers body after surfacing and the diver must account for it before repeat dives, flying, or being considered “clean”.

44
Q

ESDT define

A

Equivalent single dive time - RNT+BT

45
Q

If your SI is <:10 between dives then…

A

add the BT’s of the multiple dives and enter the T/S @ the deepest depth.

46
Q

RNT exception rule

A
  • the sum of your BT’s and chart with the deepest depth to determine ‘D’ obligation
  • choose the shortest ‘D’ obligation between your charted dive vs the RNT exception rule.
  • most likely with short SI dives.
47
Q

Diving @ altitude requires ____ ‘D’ than dives@ sea level

A

longer

48
Q

SLED

A

Sea level equivalent depth

  • cannot be used c/ equipment that maintains a constant ppO2.
49
Q

Elevation Correction Requirements:

  • 0 to 300’
  • 301 to 1000’
  • 1001 to 10,000’
  • 10,000’ +
A
  • none
  • if >145fsw
  • all dives
  • contact NAVSEA 00C
50
Q

Flying after Diving:

Ascent in altitude after diving (ex: flying, hiking, driving, etc…) increases the risk of ___, due to the ___ in atm pressure.

A

DCS

reduction

51
Q

Minimum SI required before flying depends on the planned altitude and the highest group designator obtained c/in the last ___ hrs.

A

24

52
Q

commercial airlines are pressurized to ___ ‘

A

8000’

dmt (15 decks)

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