I'm sorry but I can't find the equation that you posted that relates to the tipping can problem. Could you please repost the equation?We already did, when I posted the answer in post 3 of this thread. Its just a simple algebra and sum of the moments problem.
Tip the can
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David Redszus
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Acceleration from the standing position.
32.174 * 1.25 = 2.5 * A
A = 16.1
F=MA = 16.1 * 0.8125 = 13.1
Normal force = 0.8125*32.174 = 26.14
Fr= Mu*N = 26.14
F is less than Fr so it will tip not slip.
Acceleration from the 'fallen' position
32.174*2.5 = 1.25* A
A = 64.348
F=MA = 52.3
Fr is the same as previous
F is greater than Fr so it will slip not tip.
You will have to excuse me for not reading your post more carefully and taking note of mu. I have spent all the time I intend to on this.
32.174 * 1.25 = 2.5 * A
A = 16.1
F=MA = 16.1 * 0.8125 = 13.1
Normal force = 0.8125*32.174 = 26.14
Fr= Mu*N = 26.14
F is less than Fr so it will tip not slip.
Acceleration from the 'fallen' position
32.174*2.5 = 1.25* A
A = 64.348
F=MA = 52.3
Fr is the same as previous
F is greater than Fr so it will slip not tip.
You will have to excuse me for not reading your post more carefully and taking note of mu. I have spent all the time I intend to on this.
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David Redszus
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In a very simple, easy to understand form, the equation that describes how many Gs would be necessary to tip the can:
G = Can diameter / 2 * CGH
where CGH is the Center of Gravity Height.
So for a can that is 5 in high and has a diameter of 2.5 in, we find that
the CGH would be half the can height or 2.5 in.
G = 2.5 / 2 * 2.5 = .5Gs
The exact same formula applies to a vehicle where the can diameter is replaced by the track width. So a 5 ft wide track and a CGH of 18in would be:
60 / 2 * 18 = 1.66Gs.
If the tires cannot generate 1.66Gs, the car will slide and will never tip or roll over.
The point of it all is: the stickier your tires the more the car will lean and the closer you will get to rolling over.
The same holds true for lifting the front wheels during acceleration.
G = Can diameter / 2 * CGH
where CGH is the Center of Gravity Height.
So for a can that is 5 in high and has a diameter of 2.5 in, we find that
the CGH would be half the can height or 2.5 in.
G = 2.5 / 2 * 2.5 = .5Gs
The exact same formula applies to a vehicle where the can diameter is replaced by the track width. So a 5 ft wide track and a CGH of 18in would be:
60 / 2 * 18 = 1.66Gs.
If the tires cannot generate 1.66Gs, the car will slide and will never tip or roll over.
The point of it all is: the stickier your tires the more the car will lean and the closer you will get to rolling over.
The same holds true for lifting the front wheels during acceleration.
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David Redszus
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What we are really discussing is vehicle weight transfer. Weight transfer does not depend at all on suspension components.Wouldn't springs, and other suspension components/modifications eliminate or change the roll (lean), or have I flipped?
The only variables that determine weight transfer are: wheelbase (or track width), CGH, and G force.
Suspension components can affect the rate of weight transfer, but not the actual weight transfer.
is this what i get to look forward to when i go to college for mechanical engineering, my high school physics class is not nearly this involved 
JRog, all that and much much more. This is among one of the very first and most simple things you will learn (where David and Greezer trying to take it now has to do with dynamics and half car models and is quite a bit more complicated if you're not educated on the subject). I am not trying to discourage you, but when you start your first semester look around the room because that will be probably the last time you will see most of them and in my experience at least 90% of them will not make it to graduation with that major.
If you're capable, the only thing hard about finishing once you get past the first two years is that most instructors seem to think days are somewhere around 30 hours long and that you are taking only one class a semester. Its alot of long nights and absolutely gigantic amounts of work output, but its worth it in the end I think.
When I started at community college I think there were 200 of us, 5 of us walked at graduation. I estimate based on the content of my senior design class that there are about 60 of us to graduate this semseter on a campus of I think 20k students.
It also never hurts to hang out with ladies from the communications or arts buildings
there sure as hell won't be any to speak of in the engineering buildings.
If they're not teaching forces, acceleration, and moments what on planet earth are they teaching you in physics class?
If you're capable, the only thing hard about finishing once you get past the first two years is that most instructors seem to think days are somewhere around 30 hours long and that you are taking only one class a semester. Its alot of long nights and absolutely gigantic amounts of work output, but its worth it in the end I think.
When I started at community college I think there were 200 of us, 5 of us walked at graduation. I estimate based on the content of my senior design class that there are about 60 of us to graduate this semseter on a campus of I think 20k students.
It also never hurts to hang out with ladies from the communications or arts buildings
there sure as hell won't be any to speak of in the engineering buildings.If they're not teaching forces, acceleration, and moments what on planet earth are they teaching you in physics class?
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David Redszus
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JDavis is absolutely correct. In the scientific world there are "hard sciences" and "soft sciences". Engineering consists almost entirely of "hard sciences" which are not only rigorous in nature, but difficult to understand at first reading, and are taught by folks who know this stuff and take it quite seriously.If you're capable, the only thing hard about finishing once you get past the first two years is that most instructors seem to think days are somewhere around 30 hours long and that you are taking only one class a semester. Its alot of long nights and absolutely gigantic amounts of work output, but its worth it in the end I think.
An engineering education is not about what or how much you learn but rather how to think objectively and quantitatively.
Once you learn how to think, the technical subjects become much easier. Engineering is, in the end, simply a way of thinking and seeing the world as it really is.
Unfortunately, this skill is almost never taught in high school (even in the best schools). An engineering textbook is not a novel (or a magazine) and cannot be read as one. It takes concentration to ferret out the key principles from the clutter and chafe. Learn the underlying principles and the miriad of details will follow later.
Yeah thats what you really learn is how to think like an engineer. It is painful and nobody likes to constantly be made to feel stupid (which will happen a bunch when you're cutting your teeth), but it is quite amazing when everything sort of snaps into place.David Redszus wrote: An engineering education is not about what or how much you learn but rather how to think objectively and quantitatively.
Once you learn how to think, the technical subjects become much easier. Engineering is, in the end, simply a way of thinking and seeing the world as it really is.
The instructors have no patience for you crying and not wanting to do a ton of work. They dont care if it takes you all night or all weekend or how many other assignments you have. Also you will learn that nothing is too hard. It just seems that way when you're 20-30 years and a couple graduate degrees behind the guy teaching the class. Yes he really just did that whole lecture off the top of his head.
David if you dont mind me asking, where do you happen to be employed. You can pm me if you dont want to say on board.
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kirkwoodken
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I found this topic interesting as I reflected on "the guy who would put the $100 dollar bill on the dashboard, and you couldn't grab it when he took off". Curious, I put a $1 dollar bill on the dash of my six cylinder Ford wagon; took off and the bill slid to the floor. Another myth busted.
My son-in-law is an engineer like David: many are not. I worked with one who thought he could improve a brand new $125,000, 20 foot wide saw, capable of cutting + or _ .001" over its entire width, by cutting it in half with a torch. Not only was there no improvement, but it never worked correctly again. The company didn't fire him!!!!!!!!
Same company: An hourly person's house burned and he lost everything. He took a week off to get a car, buy new clothes for his family, find a place to live. They fired him for excessive absenteeism. It was the only time he had missed work in two years of employment.
My son-in-law is an engineer like David: many are not. I worked with one who thought he could improve a brand new $125,000, 20 foot wide saw, capable of cutting + or _ .001" over its entire width, by cutting it in half with a torch. Not only was there no improvement, but it never worked correctly again. The company didn't fire him!!!!!!!!
Same company: An hourly person's house burned and he lost everything. He took a week off to get a car, buy new clothes for his family, find a place to live. They fired him for excessive absenteeism. It was the only time he had missed work in two years of employment.
"Life is too short to not run a solid roller cam."
"Anything is possible, if you don't know what you're talking about."
I am NOT an Expert, and DEFINITELY NOT a GURU.
Kirkwoodken
"Anything is possible, if you don't know what you're talking about."
I am NOT an Expert, and DEFINITELY NOT a GURU.
Kirkwoodken
In Physics we're learning about forces, but it is a very basic class. Everything is remaining in 2-D, and we are not changing any variables, such as the velocity of a fluid, as we are currently in a fluid dynamics unit.
Since I'm in my junior year, I hope to take AP physics next year, and I will be taking AP calculus.
As far as changing the way I think, that is not a problem. I am currently in a psychology class, and my teacher is very unique. It is difficult to describe how he runs the class, however because of its small size, he places more value on the content, and how we can defend our own understanding of the content in a class debate, rather than assigning worksheets and other general homework assignments.
The thought of late nights doesn't bother me, as I have pulled quite a few "all nighters" working on homework and even papers for other clubs.
One thing I do hope for in college is that I can get involved in the SAE, it seems to be an interesting organization.
Since I'm in my junior year, I hope to take AP physics next year, and I will be taking AP calculus.
As far as changing the way I think, that is not a problem. I am currently in a psychology class, and my teacher is very unique. It is difficult to describe how he runs the class, however because of its small size, he places more value on the content, and how we can defend our own understanding of the content in a class debate, rather than assigning worksheets and other general homework assignments.
The thought of late nights doesn't bother me, as I have pulled quite a few "all nighters" working on homework and even papers for other clubs.
One thing I do hope for in college is that I can get involved in the SAE, it seems to be an interesting organization.
Dont take this the wrong way but, a few all nighters doesnt quite get it. I think I am doing 100 if I average 5 hours of sleep a night, I am very ragged by friday at 5 when my last class ends. When a major project is coming due I feel blessed if I can catch an hour of sleep in the senior design lab because I certainly wont get any at night. This is not a major for anyone who thinks college is a party all the time.
You can tell us all about how its not a problem changing how you think when you hit thermodynamics, engineering controls, or heat transfer in 3-4 years. That is just one of those things you dont know about until you've been through it. It is all very second nature after the class, but man is the price high on those little gems.
If I were you, I would not take highschool too seriously. I thought my highschool was a big joke personally. I never took a book home, or paid any attention at all in class, and took all the same college prep stuff you are talking about and somehow managed to graduate 2nd in my class. To determine who was on top they had to go back to our actual averages and then go a few decimal places. My lazyness bit me again that particular day.
I am not trying to discourage you, I think its great that you want to do it, just trying to give you a taste of the reality of it from my experience. Its a tough club to get into, the initiation is a 4 year beating. Once you get half through your jr year though, everyone usually makes it after that.
You can tell us all about how its not a problem changing how you think when you hit thermodynamics, engineering controls, or heat transfer in 3-4 years. That is just one of those things you dont know about until you've been through it. It is all very second nature after the class, but man is the price high on those little gems.
If I were you, I would not take highschool too seriously. I thought my highschool was a big joke personally. I never took a book home, or paid any attention at all in class, and took all the same college prep stuff you are talking about and somehow managed to graduate 2nd in my class. To determine who was on top they had to go back to our actual averages and then go a few decimal places. My lazyness bit me again that particular day.
I am not trying to discourage you, I think its great that you want to do it, just trying to give you a taste of the reality of it from my experience. Its a tough club to get into, the initiation is a 4 year beating. Once you get half through your jr year though, everyone usually makes it after that.
I appreciate how you are being blunt about this, I would rather be told how things will actually be so that I might better prepare myself, than have everything sugarcoated.
For me college won't be about partying, I see that it may be fun, but it really isn't worth it to me.
I figure that if I'm going to pay them thousands of dollars for an education, I should take everything from it that I can.
jdavis, might I ask where you're attending school?
For me college won't be about partying, I see that it may be fun, but it really isn't worth it to me.
I figure that if I'm going to pay them thousands of dollars for an education, I should take everything from it that I can.
jdavis, might I ask where you're attending school?
http://www.siuc.edu/ is the place I am about to escape from. The instruction is fairly good in the higher classes although there are a few who are useless.
There are several elective classes that will really push your limits and allow you to learn about what you're interested in. There is an me405 class that is an engineering based class all about the science of internal combustion engines. You will learn all you ever wanted to about crunching dyno data and developing combustion engines to meet desired constraints.
The administration is pathetic though and mostly concentrated on sports and thier pocket book. I rather wish they could understand that the alums paying for the new stadium and other projects were not there to play basketball but turning that tide is alot like trying to ice skate uphill. It is sometimes easy to believe they hate thier engineering, law, and medical students with some of the things that are allowed to go on.
I'd go to a smaller school first to get your 2 year degree. The only thing I have seen happen from going all 4 years at this university is having to go 1 more to finish up.
Your attitude is good, but let me tell you life can really get in the way of what you think you're going to do.
There are several elective classes that will really push your limits and allow you to learn about what you're interested in. There is an me405 class that is an engineering based class all about the science of internal combustion engines. You will learn all you ever wanted to about crunching dyno data and developing combustion engines to meet desired constraints.
The administration is pathetic though and mostly concentrated on sports and thier pocket book. I rather wish they could understand that the alums paying for the new stadium and other projects were not there to play basketball but turning that tide is alot like trying to ice skate uphill. It is sometimes easy to believe they hate thier engineering, law, and medical students with some of the things that are allowed to go on.
I'd go to a smaller school first to get your 2 year degree. The only thing I have seen happen from going all 4 years at this university is having to go 1 more to finish up
.Your attitude is good, but let me tell you life can really get in the way of what you think you're going to do.