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# Física

Visual Reversal

33%

Turbidity

4 times faster

20 times

#### Why does heat travel much faster in water than in air?

Because water molecules form weak bonds between themselves.

1.9 atm/bar

2.9 atm/bar

#### What is the Gauge Pressure in 18 metres of fresh water?

1.7 atm/bar (1.8 divide by 1.03)

Greater than

#### If a fully inflated balloon was placed in a cold room, what would happen to the volume?

The volume of the Balloon would decrease

#### If a balloon is filled to 2 litres at 45 metres, and then released, assuming that it doesn’t explode, what will it’s volume be upon reaching the surface?

11 litres
(Using box method.. 2 x 5.5 = 11)

#### Approximately how much air mist be pumped down from the surface to fill a 60 litre container if the container was in 50 metres of water?

360 litres
(Using box method.. 60 x 6 = 360)

#### What is the partial pressure of Nitrogen in Air if breathed up a mountain, where the surrounding pressure is 0.6 atm?

0.48 %
Even this can be worked out by the Box method!
the absolute pressure is 0.6 ( it says so in the question!) the approximate percentage of Nitrogen in the air is .80% so the calculation would be: 0.8 x 0.6 = 0.48)

#### A diver breathes from a cylinder that contains 0.03 % carbon monoxide. At a depth of 25 metres, this would have the same effect as breathing … % at the surface?

0.105 %
(Using box method: 0.03 X 3.5 = 0.105)

#### At a depth of 20 metres, approximately how much denser is the air a diver breaths as compared to the surface?

3 times
(even this can by solved using box method: 1 x 3 = 3)

#### If a diver breathes a complete cylinder of air in 70 minutes. at the surface, how long would it take to breathe the whole cylinder at 25 metres?

20 minutes
Using the box method: (70 divide by 3.5 = 20 minutes)

#### If an object weighs 720 Kg and displaced 120 litres, how much more fresh water would need to be displaced to bring the object to the surface?

600 litres
( as it’s in fresh water, 720 – 120 = 600 )

#### If an object weighs 377Kg and displaced 89 litres, how much more sea water would need to be displaced to bring the object to the surface?

277 litres
( as it’s in salt water, 377 divide by 1.03 = 366.
Then .. 366 – 89 = 277)

#### If a full scuba cylinder was placed outside in full sunshine on a hot day. What would happen to the pressure inside the cylinder?

The pressure inside the cylinder will increase

#### If an object that weighs 970 Kg and displaced 420 litres, is in fresh water how much air would need to be added to a lifting bag to bring the object to the surface?

550 litres
( as it’s in fresh water, 970 – 420 = 550)

#### If an object that weighs 68 Kg and displaced 15 litres, is in salt water how much air would need to be added to a lifting bag to bring the object to the surface?

51 litres
(as it’s in sea water, 68 divide by 1.03 = 66
Then .. 66 – 15 = 51 litres)