Quiz - Physics - Displacement

If an object that weighs 85 kg/187 pounds is neutrally buoyant in salt water, what is the volume of

  • a. 8.5 liters / 3 cubic feet

    Votes: 3 3.4%
  • b. 82.5 liters / 2.9 cubic feet

    Votes: 75 85.2%
  • c. 87.5 liters / 3.2 cubic feet

    Votes: 8 9.1%
  • d. 170 liters / 6 cubic feet

    Votes: 2 2.3%

  • Total voters
    88

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Dimensional analysis got me through 2 quarters of upper division physical chemistry at UCSD, scuba is a piece of cake :)
Did you use this goalpost thing?
 
Dimensional analysis got me through 2 quarters of upper division physical chemistry at UCSD, scuba is a piece of cake :)
Did you use this goalpost thing?
UCSB and Electrical Engineering for me, and I couldn't agree more. Never heard of the goalpost thing until just now.
 
Did you use this goalpost thing?
No, never heard of it, straightforward math: this post question is a good example:
187 lbs/64 lbs/cu ft = 2.9 cu ft
You can do incredibly complex problems if you make sure that the units work out :) Does help if you know how math works.

Maybe goalpost was "new" math, I'm a lot older than that. I used a sliderule in my freshman year before they decided to allow calculators. My basic calculator with square root cost me $100 in 1972,
 
Just gonna drop a couple of things right here:
- Mars Lander. Whoops.
- Why do so many "metric" countries make things that are 2.54cm and the like?
- Why did we have to "make life so much better" when it didn't actually eliminate the great problem that was "solved" by the metric system? 60 seconds, 60 minutes, 24 hours (and 12 hours x 2), 7 days, 28-29-30-31 days, 365 days, 12 months, 4.xxx years.

We still live with this so tell me again why is the metric system so awesome? So end all be all?
 
AF8EE6F2-E788-4E73-859A-C85510E4E54C.jpeg
 
When you grow up with a system it is easy, when you have to change, it is hard. We may not agree on feet or meters, or psi or bar, but we can agree on minutes of NDL or minutes of deco :)
 
When you grow up with a system it is easy, when you have to change, it is hard. We may not agree on feet or meters, or psi or bar, but we can agree on minutes of NDL or minutes of deco :)
I did grow up with THREE systems, not one.
And I had to switch when I was almost done studying, at 23 years old.
It was not so hard, and after the switch I immediately perceived the great benefits of SI above all the other systems.
 
I did grow up with THREE systems, not one.
And I had to switch when I was almost done studying, at 23 years old.
It was not so hard, and after the switch I immediately perceived the great benefits of SI above all the other systems.

(Playing Devil's advocate here - I'm glad I dive with metric units and use SI/metric units at work) why not use the SI unit for time (seconds) while diving? And could one be prosecuted for measuring time time in minutes, hours, days or years?

I've been to Italy once and I'm pretty sure the posted speeds were in km/h rather than m/s. I doubt the highway engineers would be prosecuted if somebody drove through an 80 zone at 80 m/s (288 km/h = 179 mph).

Ed: these quizzes are good fun. Please keep them up.
 
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