Quiz - Physics - Displacement

[saxman242]

I truly never heard of a "kilopond". Here when I was a student we did use kgf (kilogram-force), as SI became mandatory by law in 1981, and so for most of my school and university a number of professors were using the old units.
In 1981 everything changed. I graduated in 1982, and so I had to write my Master Degree Thesis in SI units, after having studied for 18 years with the other system. It was not easy. But everyone had to do this change in 1981...
Despite this, no one ever called a kgf a "kilopond". Probably this term was used only in some country.

That doesn't surprise me that much. Kilopond definitely is a dated term. kgf, on the other hand is still in common use in many circles.

 

[Joneill]

What's "ha"?

Sorry - glitch as I was multitasking. I fixed it.

 

[vjb.knife]

What is the salinity and temperature of the water?

 

[TMHeimer]

I finally got my calculator and did 187 divided by 64. Equals 2.92 (and more fractions) pounds. I would think that something displacing only 2.9 pounds would at some point come to the surface and barely float. With this type of question I don't think you can round off.

My take on metric--
Yes, I recall the U.S.' metric attempts of the 1970s. A few kilometer signs still remain in the Northeast.
Canada started moving to metric about 5 years before I arrived in 1977 There were still km. and mile signs in Manitoba in '77.
Of course, the vast majority of Canadians now know only metric--some my age and older still use miles, feet, Fahrenheit, pounds, etc. but we can interchange them for the metric equivalent without doing any calculations.
So, Pierre Trudeau was right in that Canada going metric would be a good thing for future generations (like NOW). Interesting thing is that aside from maybe a few scientists in 1972, probably hardly anyone supported going metric and would've voted for it back then. Was that the best way for Pierre to serve the people who were of voting age at that time?
Do we do what the present population overwhelmingly wants now or enact laws for the benefit of their children & grand children?

 

[saxman242]

I finally got my calculator and did 187 divided by 64. Equals 2.92 (and more fractions) pounds. I would think that something displacing only 2.9 pounds would at some point come to the surface and barely float. With this type of question I don't think you can round off.

Units are critical here. 187 lbs divided by 64 lbs salt water per cu ft gives you a displacement of 2.9 cubic feet of salt water, not 2.9 lbs.

 

[rhwestfall]

So hard....

my biggest hurdle was to use 64 as I almost exclusively dive fresh water (62.4)...

 

[rhwestfall]

Sorry - glitch as I was multitasking. I fixed it.

What fun is that? It now invalidates our whole sidebar....

 

[tursiops]

So hard....

View attachment 579819

my biggest hurdle was to use 64 as I almost exclusively dive fresh water (62.4)...

What is the purpose of the vertical line on your piece of paper?

 

[rhwestfall]

What is the purpose of the vertical line on your piece of paper?

Called the "goal post method" and is used to work through units manipulation. If there were more components to use in the equation, there would be more compartments...

 

[tursiops]

Called the "goal post method" and is used to work through units manipulation. If there were more components to use in the equation, there would be more compartments...

Hmm. Never heard of it. I just write it out...seems an unnecessary add-on. "Equipment solution to a skills problem."