Physics Question...

[Easdem]

There is a question in a quiz on the PADI DM e-learning that I dont get the logic on...It goes like this:

If an object is neutrally bouyant in seawater it will _____ in fresh water.

a. sink
b. float
c. remain neutral
d. alternate sinking and floating

I think that the answer is A but the module says its B. ??? Am I missing something...

 

[BabyDuck]

ok, take it from what you know. if you need x lbs to be neutral in salt water, what would that same amount of lead make happen in fresh (with the same suit & amount of air in bc, etc)?

so i'm with you!

 

[Bubbletrubble]

Is that the exact wording of the question and possible answer choices?

 

[Easdem]

This is the question exactly as it's written and the answer choices.

 

[cool_hardware52]

There is a question in a quiz on the PADI DM e-learning that I dont get the logic on...It goes like this:

If an object is neutrally bouyant in seawater it will _____ in fresh water.

a. sink
b. float
c. remain neutral
d. alternate sinking and floating

I think that the answer is A but the module says its B. ??? Am I missing something...

Salt water ~ 2.5% (1/40) more dense than fresh water.

If your object is neutral in salt water then it's density is equal to density of the salt water.

That means it will be *more* dense than fresh water, and it will sink.

Sounds like you found a bug in the materials. Good catch.

(If your object is a brand new diver the answer is D )

Tobin

 

[Hallmac]

I dont get the logic on...It goes like this:

If an object is neutrally buoyant in seawater it will _____ in fresh water.

If you will permit me to assist you in reasoning it out.

Which is denser salt water or Fresh?

 

[Easdem]

here is a screenshot, I thought my logic was right. I will try to report it....

 

[redacted]

OK, so PADI got a 95. That's still passing, isn't it?

Maybe it is their way of testing who really understands the subject matter. Or of demonstrating that it really is not critical. Ascend slowly, don't hold your breath.

 

[Teamcasa]

Cubic foot of seawater = 64.0 Lbs +/- .5lbs
Cubic foot of fresh water 62.4 pounds +/- .2lbs

Your object is natural in seawater so it must weigh 64lbs. Drop in fresh water and down it goes.

 

[Crowley]

The question is directly from the old written exams.

The answer is A, it will sink - if the module says B - and one of the crappy things about the e-learning program is that whilst I agree with the general principle, if done correctly, we don't, as instructors, have full access to the program - if there's a bug, please inform PADI - they will fix it. Eventually.

C.