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Hillwilliam -> RE: Generation Gap (4/19/2016 12:18:02 PM)
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ORIGINAL: Phydeaux
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ORIGINAL: Hillwilliam
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ORIGINAL: bounty44
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ORIGINAL: Hillwilliam
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ORIGINAL: Phydeaux
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ORIGINAL: bounty44
in principal, im in general agreement.
I know on the whole though, students, at least many students of today, would complain vociferously about something like that and unfortunately, the administration would back them up.
once in a lab I gave the students all the apparatus they needed in order to find the answer to a particular question---and wanted them to figure it out based on the tools at hand. eventually they did, but in the meantime there was a lot of angst directed at me with "why don't you teach us??" being first and foremost.
I bet you would have liked it---figuring out center of gravity on a human body with two doctor office scales and a long plank.
Great job.
Piece of cake to solve tho.
Lie the plank so either end rests on the scales. Calibrate to zero.
Lie the person on the plank.
The ratio of weights projected along the plank is the center of gravity of the person.
Close, but no cigar.
The center of gravity or physical center of any 3 dimensional object (including humans) is a point in 3 dimensions which would commonly be expressed by its x, y and z coordinates.
The above experiment only determines the z coordinate (assuming that z is the vertical axis of the human while standing) of the location of the center of gravity. This gives the location of the plane where the desired answer (a point) is located. Due to the fact that there are an infinite number of points in a plane, the answer is nowhere close to the center of gravity.
Had you been telling them to locate a balance point, you would have been correct.
Unfortunately, you failed 10th grade geometry while attempting to teach physics.
instead of being a pompous and pedantic ass, you could rather have given some grace and understand that we're colloquially referring to the height of the center of gravity, knowing that the actual point would exist internally.
that takes care of your x, y and z axis points.
and no, there is only one point given an entire human body.
"center of gravity:
"imaginary point through which the resultant force of gravity acts on an object; in the point at which the entire weight of the body may be assumed to be concentrated; the point about which the torques created by the weights of each of the body parts balance; the point of balance of the body."
from biomechanics of sport and exercise by peter McGinnis.
"center of gravity:
"a body's center of gravity, or center of mass, is the point around which the body's weight is equally balanced..."
from basic biomechanics by susan hall.
and yeah, I know, as did my students, and I trust phydeaux knows, that the point changes according to posture.
Maybe I was referring to the person who posted this (or the teacher who wrote what he quoted and claimed as his own) was complaining about young folk who have no critical thinking skills. The irony is that the author likewise has no critical thinking skills when they read this out of the teacher's manual or they would have realized the fallacy.
If you had known, OR your students, OR Phydeaux, you would have used the proper terms.
Or maybe you would read the links and see that the proper term is actually center of gravity; that the damn near universal convention is to measure only in terms of height.
Probably not tho.
Going by your definition, the equator (or prime meridian) is the center of the earth.
The center of gravity of a 3 dimensional object is an individual POINT, not plane that is typically within said object.
Face it. You fucked up by the numbers using what I feel just might be a made up story.
Why do I think so? A typical HS whether it has a few hundred students or several thousand will have exactly ONE medical scale.
Said scale will be under the care of the football and/or wrestling coaches.
How do I know? I taught science including AP physics and coached wrestling for several years.
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