Motorycle Braking Distance

[Z_Fanatic]

ve·loc·i·ty ( P ) Pronunciation Key (v-ls-t)
n. pl. ve·loc·i·ties

1. Rapidity or speed of motion; swiftness.
2. Physics. A vector quantity whose magnitude is a body's speed and whose direction is the body's direction of motion.
3.
1. The rate of speed of action or occurrence.
2. The rate at which money changes hands in an economy.

ve·loc·i·ty (v-ls-t)
n.

Rapidity or speed of motion; specifically, the distance traveled per unit time.

I used the term loosely you see, not as a component to relate to physics.

Anyway, I am not sure about the car, but I think that's what beast tried to say - as you get down lower range of speed in bikes, you can apply more pressure, which is obviously stopping quicker than a car.

[Beast22k]

Originally Posted by aussieidiot

ok I'm not the best at physics (passed higher school cert and 1st year uni) but if both parties are travelling at the same speed (velocity is only speed in a direction). both apply brakes at the same time but at a variable due to braking abilities. Wouldn't it be that the shorter the distance equal a shorter time. Braking variables aside due to abs and driver ability and all that, in my mind the shorter the distance the shorter the time. I do get what you are saying about the speed range. We have road safety adverts saying half your speed is taken off in the last 5m (16 feet) therfore a car can decelerate evenly to a stop whereas a bike takes most of its speed of later but at a much higher deceleration to be "quicker"

OK... I will explain to you with an example... probably not how it happend but a possibility::


You have your car and you bike both going at 60m/h when the brakes are applied. Hypothetically it will take the car 6 seconds to come to a stop and the bike 5 seconds to come to a stop... this may be longer or shorter than it took them to stop but it will allow me to explain it easier for me.

So you have the car stop at a rate of -10m/h/s alright... so in the first second it will slow down to 50mph and causing it to have traveled an average distance of .0153miles. The next second it slows to 40 and travels an average distance and so forth. In the end the car has taken 6 seconds to stop but has traveled an average distance of .05miles.

The bike on the other hand... as Z_fanatic pointed out::

Originally Posted by Z_Fanatic

as you get down lower range of speed in bikes, you can apply more pressure, which is obviously stopping quicker than a car

So with that said... your bike in its first second hypothetically slow from 60m/h to 55m/h and travels and average distance of .016miles, then it slows to 50m/h and travels .0146miles, then slows to 35m/h and travels .0118miles, then slows to 20m/h and travels .0076miles, and finally comes to a stop to finish with an additional .0028miles... thus totalling up to be a distance of .0528 miles in 5 seconds.


Again in no way am I saying that this is exactly what happened it was just a hypothetical scenario that I created and solved to show you and help you understand that it is in fact possible to the upmost degree(not trying to sound rude in that statement if you do take it that way).


Anyway I hope this helps...
Later

[Z_Fanatic]

lol, damn it's funny, but with your hypothetical equation, I am getting totally different/off numbers. how'd you get your average distance per sec?

[Beast22k]

Originally Posted by Z_Fanatic

lol, damn it's funny, but with your hypothetical equation, I am getting totally different/off numbers. how'd you get your average distance per sec?

OK... first off everything is a huge average between 2 vehicles. The different velocities at each second were compleately made up by me merely to demenstrate that it is false to say that whichever vehicle stops the quickest will require the least distance to stop. Now to get to your question... to get an average distance when given initial and finishing velocities and time you must first get the average velocity(and this is for each interval just to make try to cover every possible question)... so you take (Vf + Vi)/2. Once you acertain that you must then figure how far you travel with that average speed in the time given(which in my scenario is 1 second intervals). In order to perform this correctly you must first convert m/h into m/s by taking that average speed and dividing it by 3600(I assume you want to know why you use that number... well it is because to convert from hours to minutes you must multiply by 60 and then to get to seconds you must multiply by an additional 60... to shorten it up 60*60=3600 so you can shorten the process and just multiply hours by 3600 instead... sorry I know some of this is probably repetative but I am just trying to ensure I don't leave anything out)... so now you have taken m/h and made it (m/3600h) = (m/s). Now because it is in m/s and we are in 1 second intervals there is no more math to do and however many average miles per second you are going is now the average distance as well. Now all you do is take the average distance for each interval, add them together and you have your total distance traveled... again as an average.

If I recall correctly there is a much simpler way to do all that by incorperating Calculus into the Physics into one simple equation but I have been out of both Calculus and Physics since summer started the last week of May and I have placed all my Calculus into the back of my mind... most of the physics too... I am just applying basic principles in this scenario to make it easy on me. But anyway that is how you do it...

"Class dismissed"

Later

Ohh and if you have any other questions feel free to ask... that is pretty damn jumbled up right there so I understand if something is unclea... you won't be irritating me any... I am fucking bored right now so it will keep me entertained.


EDIT::After reading your question again I think I might have over- answered.

[Z_Fanatic]

yeah thanks, got it, I always forget to convert in the end, in this case, m/h to m/s.

personal question, since you took cal and physics, are you in college or high school?

So with that said... your bike in its first second hypothetically slow from 60m/h to 55m/h and travels and average distance of .016miles, then it slows to 50m/h and travels .0146miles, then slows to 35m/h and travels .0118miles, then slows to 20m/h and travels .0076miles, and finally comes to a stop to finish with an additional .0028miles... thus totalling up to be a distance of .0528 miles in 5 seconds.

ok so your first sec. interval is going from 60 to 55, implyng slow deceleration at high speed range. 2nd sec, 55 to 50, same rate. but then you jumped from 50 to 35, implying rapid deceleration for lower range of speeds. and the pattern follows until 20 mphs, keeping that 15 mph rate of declination, and once again, it shifts from 20-0, whoa... some figures you got there. I doubt that's how bikes function though, I can understand the top range, but I think perhaps the rate of deceleration is higher at 55-40 than explained. I know you tried to get a point cross. But there has to be a constant increasing rate of deceleration in bikes in terms of capabilities, not so much the consistency in how fast it loses momentum like in a car, but rather the inclination in deceleration. Which is evident in the lower range, but not so much in the higher. This of course is theoretical, not accounting the rider's input.

[Beast22k]

Originally Posted by Z_Fanatic

personal question, since you took cal and physics, are you in college or high school?

I am 16 going into my Senior year of high school but the classes I took... well the Calculus one... was an AP class for college creditt as long as I passed the final test.

As for the hypothetical example... I am most possitive that the numbers given are off... I just set something up to as you said "get a point cross" and show aussieidiot an example of how one vehicle could slow faster overall yet travel a longer distance to do so than another vehicle. All in all however I hoped this has helped out...

Later

[aussieidiot]

i haven't done physics for over 10 yrs so i had to try and remember all the formulae and theories. you have explained it just fine although being from a METRIC country and given away the old ways years ago i still understand. he he any chance for a dig

[Z_Fanatic]

took high school Cal once, it's nothing like college Cal of course, hell, College Algebra is more difficult than high school Cal/AP Cal. Probably taking physics this semester or next. Hopefully, I dont get probation in college. that would be first.

[speediva]

Shit, I'm a math education major, and I've NEVER had physics in 4 years of HS and 4+ years of college!!! I guess that's why I was unsure of what's up. It seems like you could have taken the derivitive at some point on something in that big equation, but not knowing how it works or why, I don't think I could say anything more.

[Z_Fanatic]

graduated early or something? you'd have to closer to 21-22 at least.

[R1-rider]

who cares

just try and stop before you hit something

[Z_Fanatic]

that wasn't the point.

[speediva]

I'm 21. Will turn 22 in August. I'm an old fogie 'round these here parts.

[aussieidiot]

what does it mean if your 30 then. should i be dead and buried?

[speediva]

Originally Posted by aussieidiot

what does it mean if your 30 then. should i be dead and buried?

Yes, but only b/c you're from Oz.