Sorry but it was 3/100's as a percentage of the total length of the bar and not 3/100 of an inch. It is a poorly worded problem that had me fooled in the beginning.
I had to read it twice... it says per 4" and as a machinist we think per 1". so while John it right, in the real world no one would state the problem that way
As a non-machinist, I was going to say something like that. If somebody says they need to shave off a couple thou, they mean that they need to shave two thousandths (0.002) off the entire piece. It’s an actual measure of what comes off; it’s not a proportion.
As a person who has worked in construction; fabrication and machining I get irritated at how text book questions are phrased. I understand that they wish to ask "real world" questions, but sometimes they come across as odd. Three hundredths is a measurement, so it could be argued that is how much Les is supposed to "shave off". Also, It doesn't say which face of the bar, it could need it from the long side etc...
I get your point - really, I do. But, we are only given one dimension - 4 inches. So, it is simple arithmetic - 4 inches x 0.03 = 0.12 inches. Converted to fractions, rather than decimal, gives us 12/100 of an inch, simplified to 3/25 (which, of course, is an odd fraction and not one found on a ruler, measuring tape, or even a caliper). This is just what you're going to get when a mathematician writes a word problem about an engineering task.
In manufacturing the terms like take off 3 hundredth's or 3 thousandth's would be implied " of an inch " so your wording made it vague. If you said take off 3 hundredth's of the total length of a 4 inch bar would remove the vague statement. :)
3 one hundredths from 4 inches equals 3 inches and 97 hundredths. That is a fact and this answers the question. It does not mater how thick something is, if you remove 3 hundredths then the original prince will be less by 3 hundredths. Or you can ask what is 3 hundredths of 4 inches. But you did not….
@GaryBricaultLive if you tell any machinist or engineer to remove 3/100 or 3/1000 or 3/10000 it is understood to mean "of an inch". Every. Single. Time. You're right it was poorly worded if he expected anything other than how I and many others interpreted it.
In the real world measurements are in x/1". Upon first read i missed the per 4" BECAUSE NO ENGINEER WOULD WRITE IT DOWN LIKE THAT!!! IT WOULD HAVE BEEN WITTEN AS: Remove 3 hundreds of an inch (0.03) per inch of thickness 4" . .03 * 4 = .12
I would advise Les to query the request to remove all the ambiguities. Three hundreds as a length is 0.03”; three hundreds off every inch of a 4 inch bar is 4 x .03 or .12”; three hundreds off the width of a bar 4” long decreases the (unknown) width by 0.03” and leaves the length unchanged at 4”. I did like the idea of taking .03 off the radius and decreasing the diameter by .06!
I’m also a machinist for over 40 years and I would have taken .030” off the bar. John obviously is not a machinist. In addition to him not knowing how trades people talk about machining, but most machinists talk in terms of “thousands” of an inch, 30 thousands of an inch would of been removed from the block of steel. Why do I say that? Because (as every machinist knows) the machines are graduated in thousands of an inch, not “hundreds” of an inch
In inches, 4" x .03=.12" which is just under 1/8" (.125"). Or in decimal feet (my preferred method) .3333' x .03 = .01' which is just under 1/8" (.0104'). If I gave my steel fab shop guys or my machinist a measurement of 3/25", he'd think that I had no clue what I was doing. What tool would you measure 3/25" with?
Just a convention note; a machinist could of course cut 3/25 of an inch off however that is an unconventional communication for machinists, they would for the sake of clear understanding remove .120 inches.
Upon your concluding another session of engaging conversation, an advert interrupted and began before you could return to the problem proper. Considering RU-vid's increased propensity to insert advertis, perhaps you could consider the possibility of reducing the amount of engaging though tangential conversation. If only RU-vid would limit adverts to entertainment videos and allow academic and informative videos to run without distractions.
Try adding the extension "Adblocker Plus" or "Ad Blocker for RU-vid" to stop youtube ads. (Used with Firefox). RU-vid has been trying to circumvent these ad blocker extensions recently, but the blockers still seem to work OK.
The answer probably should have read as 12 hundredths of an inch. 3/25 is not a practical way to read inches. It did not at any time ask you to shave 3 hundredths of an inch. A lot of us are looking at this from a practical / real world stand point and not as just a math problem. this is the rest why he says to read the problem multiple times. If you handed this straight to a machinist he is probably going to assume business as usual an shave .03 in off the bar.
I haven't watched the video yet, but the description of the bar is inadequate to calculate the equation. What exactly are the dimension of the bar? Is the bar a 4 inch cube, a 4 inch diameter round bar, or is the 4inches simply one dimension of one side of the bar. Moreover, how long is the bar, and is that area to be ct off to be from the end, top or side of the bar? I just thought of another twist. How about 300ths of a chamfer on one edge of the bar. But seriously, make the equation taking 3000ths off from a 4" x 4" x 12' bar with the area to be removed coming from the top width of the bar.
is 3-hundredths 0.03" or 3% A S S U M E 3-hundredths = 3/100 = 3% 4inches = 16×4 = 64/16 inches (64/16)×(0.03) (64×3/16×3)(0.03) (192/16)(0.01) 1.92/16 ~1/8"
I hope this is trick language...because in real life no-one would ever talk like that: If someone were being giving instructions, it would be specified that it was 3 hundredths of an inch to be shaved off...or 3% of the total thickness of the block. so the answer is .03 of an inch. Instructions would never be stated simply as 3 hundredth. Now, having seen your answer, I see that it is total BS because, again, if someone were being told to shave off 3% of the total thickness off of a block that would be the language...or 12 hundredths or 3/25ths of an inch. In fact the language would almost certainly be 120 thousandths. It would NEVER be 3 hundredths without being told hundredths of what. If this is your way of testing whether the listener knows a whole is generally considered to have 100 parts, or 100%, it's a poor way of doing it....and, for that matter, you would never award 200% for a completely correct answer! An answer can be less than 100% correct. But, aside for extra credit for extra work, the answer itself can never be more than right.
Three hundredths of a four inch bar is three percent of the bar. Each of the four inches is 25 percent of the bar. Therefore the answer is 3/25 inches.
This question is an example of the worst kind of garbage math question possible, it completely ignores proper terminology. Shaving off a 4 inch steel bar has a shaving length of 4 inches as a shaving is a continuous strip removal, the depth of the shaving is 3/100 of an inch. Please rephrase the question so it makes sense and is not ambiguous, be exact in your terminology and state clearly what you are asking for.
A poorly worded question. If you "turn off" 3/100" off a circular bar, you will lose 6/100". The more times you read the question, the more options there are, all generated by what the questioner meant by "shaving off".
Yes again another poorly worded problem. The question being asked is to remove 3/100's as a part of the total length of the bar and not just 3/100 of an inch.
