Quiz - Physics - Minimum Amount of Water That Must Be Displaced

[scubadada]

Spoiler: Imperial Solution

(385/64) - 4 = 2.02 (yep, splitting hairs, but 2.0 won't cut it)

You give it a little tug, and up it goes

 

[rhwestfall]

You give it a little tug, and up it goes

lifting gear is likely not neutrally buoyant....

 

[tursiops]

Some of you guys are doing a lot of guessing on the constants! Pedro provided them for you, early on. Even if you think these are wrong, they ARE what the question and answer are based on.

The following are the constants used for the PADI Dive Theory Exam:

Metric

• 1 litre of salt water weighs 1.03 kilograms
• 1 litre of fresh water weighs 1 kilogram
• Pressure increases by 1 ATM every 10 metres of salt water
• Pressure increases by 1 ATM every 10.3 metres of fresh water
• Pressure changes per unit of salt water = 0.100 ATM/m
• Pressure changes per unit of fresh water = 0.097 ATM/m

Imperial

• 1 cubic foot of salt water weighs 64 pounds
• 1 cubic foot of fresh water weighs 62.4 pounds
• Pressure increases by 1 ATM every 33 feet of salt water
• Pressure increases by 1 ATM every 34 feet of fresh water
• Pressure changes per unit of salt water = 0.445 psi/ft or 0.0303 ATM/ft
• Pressure changes per unit of fresh water = 0.432 psi/ft or 0.0294 ATM/ft

 

[BlueTrin]

I learned today that sea water density can reach 1.05 at depth:

Seawater - Wikipedia

 

[Scraps]

I learned today that sea water density can reach 1.05 at depth:

Seawater - Wikipedia

That’s the kind of knowledge that can keep this anchor on the bottom.

 

[tursiops]

I learned today that sea water density can reach 1.05 at depth:

Right, in the deep deep ocean. So much for water being incompressible!

 

[tursiops]

Spoiler

If you do the problem in metric, it works better. Too many rounding uncertainties in the Imperial version.

 

[HKGuns]

I misread the question. Going too fast while multi-tasking.

 

[tursiops]

I misread the question. Going too fast while multi-tasking.

Best thing I learned in cave diving: Slow is Smooth, and Smooth is Fast.

 

[rhwestfall]

Some of you guys are doing a lot of guessing on the constants! Pedro provided them for you, early on. Even if you think these are wrong, they ARE what the question and answer are based on.

And my answer using those was?