MotorBike physics and Life hacks..

bike4life

Well-Known Member
Local time
9:09 AM
Joined
Mar 19, 2018
Messages
1,290
Location
Central New Jersey
Bike4life, which is stronger? A solid 8" pipe weighing 1lb or an 8" tube weighing 1lb both made of steel?
Ok sorry didn’t reply soon as stupid hotel gave me food poisoning. Ok I think u mean a 8” solid round stock of 1lb and a 8” hollow round stock of like 1/3lb. In this case if they were columns or beams, the solid would be stronger but not by much, they would be very close. The reason is that the OD is where the most force is and as u approach the center, the force becomes 0. Take a piece of foam with nails on the top and bottom. When bent, the nails bend inward (compression) on the top and the bottom the nails bend outward (tension). But at the very center longitudinally
 

bike4life

Well-Known Member
Local time
9:09 AM
Joined
Mar 19, 2018
Messages
1,290
Location
Central New Jersey
You say the bending strength of a solid shape and give it a formula. A 2x6 is not 6"tall nor is it 2" wide. 5.5^3x1.5=249 and none of this works because not all "solid shape" materials share the same structural values. What works for wood won't work for steel, and the bending point (deflection) will change depending on the camber, and the distance spanned. If you place 249 lbs on a 2x6 spanning 2' it won't budge. Span it 20' and you might find a moment. If your giving out life hacks, please include all the facts.
At least your thinking though. When I was your age all I was thinking about was how I was gonna be able to have enough money for a bag of weed, gas for my car, and a good plan to get into my girls pants over the weekend.
Yeah I know that with the distance. No duh Sherlock but I didn’t include it as it’s a constant. Like when building a table or a bridge it’s a set distance u can’t exactly make it shorter unless u use columns, which are sometimes impractical and ugly.

Also what works for wood will work for steel for all practical purposes. The only thing different is their modulus of E and this is a coefficient so just multiply your data by it at the end. Also I know a 2x4 is 2x3.5. I just rounded for easy calculations.
 
Last edited:

bike4life

Well-Known Member
Local time
9:09 AM
Joined
Mar 19, 2018
Messages
1,290
Location
Central New Jersey
Nobody is going 1/2 the speed of light. You will have issues with measuring it due to the time difference.

There is a lot more to a bolt than the minor diameter of its thread. Go back to school kid.
Whatt... yeah there is more like tpi, and other stuff but that’s noise. For our purposes the minor diameter is what matters most. The other stuff has little affect and would be more complex math
 

darwin

Well-Known Member
Local time
7:09 AM
Joined
May 26, 2008
Messages
5,239
Most people w/o thinking about it will say a solid rod weighing 1lb is stronger than a tube weighing 1lb, both steel. Actually the tube is stronger. Remember both have the same amount of steel in them by weight.
 

bike4life

Well-Known Member
Local time
9:09 AM
Joined
Mar 19, 2018
Messages
1,290
Location
Central New Jersey
Most people w/o thinking about it will say a solid rod weighing 1lb is stronger than a tube weighing 1lb, both steel. Actually the tube is stronger. Remember both have the same amount of steel in them by weight.
Yeah before when u said 8” it was confusing as a solid tube of 8” is stronger than a hollow tube of 8”, as therefore the solid would weigh more, so how could they both be 1lb. Good u rephrased it. Drilling out the center of a solid will make it weaker, this is intuitive. As u could crush it easy by stepping on it or bending it.

Now a solid tube of 1lb is weaker than a hollow tube of 1lb. The reason is this implies that the OD of the hollow is larger, like 10” hollow vs 8” solid. This is because most forces increases as u go away from the center. In fact, the dead center to 1/10000000” should have 0 force at all. So with a solid, u have waste material that doesn’t do much as a hollow is more efficient.
 

bike4life

Well-Known Member
Local time
9:09 AM
Joined
Mar 19, 2018
Messages
1,290
Location
Central New Jersey
At least your thinking though. When I was your age all I was thinking about was how I was gonna be able to have enough money for a bag of weed, gas for my car, and a good plan to get into my girls pants over the weekend.

😂 lol. I really wish I had the same mentality. Unique/unfortunate circumstances made me an outsider to this. Ie for one I don’t go 2 my home skool with like 2000 kids which I’ve known since like 1st grade. I go to this small smart kids magnet skool with only like 70kids in the grade that is defiantly less open and fun. Some of the kids OCD about skool and are boring. A select few of them r wannabe mean/tough ppl b/c they probably feel helpless? If they try to boss me around I just laugh. The other group that do stuff is closed off to most kids of outsider status for various reasons. I am of outsider status even though I try not too...The other group just play video games. When I was a kid like 8, I won an x box in a raffle but my parents took it. I bought in to the propoganda about video games being bad, and I don’t really regret much as I am now 2 busy with welding and what not, but just shows some of the lack of freedom imposed. Hell my mom doesn’t even like me building stuff, thinks it’s a distraction. But I still do it during the day when she is out of the house. I garuntee if I didn’t build stuff as my hobby, I would have became one of those suicidal mental cases. I knew a kid in middle skool who never talked....Overall makes me pretty dam sad. Luckily I hack the system by copying hw during class and by finding out tests so I don’t have to do much work. I wouldn’t be able 2 handle the work crap they give us and the lack of friends simultaneously. Unfortunately never really interacted much in middle skool, so don’t really have those existing connections. The only reason I know most of this math stuff is b/c one thing going 4 me is whenever I see a big building like an airport or bridge I want to know why the architect and engineers made these choices. Like when I was 10, I would stare at the giant gausset plates in the big airports and wonder about the truss structures and what not. I kinda feel like I wasted a chunk of time at this new skool, Better luck next time... the only thing going 4 me is I have a few really good ideas for small biz/entrepreneurship Which would if I want allow me to retire really young like at 30 something. Overall though I feel like this was inevitable and somehow necessary in a crazy way 4 me to be what I’m supposed to be, whatever that is. At least it helps me sleep at night....
 
Last edited:

darwin

Well-Known Member
Local time
7:09 AM
Joined
May 26, 2008
Messages
5,239
We had the same career goals when younger, throw in some alcohol for me though.
 

Tony01

Active Member
Local time
6:09 AM
Joined
Jun 21, 2016
Messages
367
Location
sf bay area
Whatt... yeah there is more like tpi, and other stuff but that’s noise. For our purposes the minor diameter is what matters most. The other stuff has little affect and would be more complex math

Sorry, but you have no idea what you are talking about. You are just adding to the garbage that is the internet with posts like this. Why don’t you get a degree in physics first before posting. Maybe then you won’t have to start a thread about a 50mph pusher trailer.
 
Top