Poll of the Day > Anyone good at math and physics?

(+) Yeah! (+)

Need some help figuring what speed I would have had to be driving to go X distance in X amount of time.

Or where I would have been at in the X distance factor while driving the speed limit.
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88mph
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Well I said 200. So that's close.

Jk it's not close.
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X is distance and t is time.

X = X/t

Xt = X

t/1 = 1

t

Therefor time is time.
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So the time is 5.5 seconds, and the distance is 140.65m.

Also, this is from a dead stop, making a right turn.
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zebatov posted...

So the time is 5.5 seconds, and the distance is 140.65m.

so yu need to go 25.52727272727272727272727 m per s
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What level of physics is this?
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The relationship between distance and time is:

distance = speed * time

If you're trying to solve for the amount of time it would take to reach a given distance, just divide the distance by the speed limit (distance / speed = time).

And likewise, given distance and time, just divide distance by time to get speed (distance / time = speed)

If you are given neither distance nor time you will need to pray to Cthulu to get the answers from the deepest darkest parts of the world
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I'm good at all math related questions, but you have to take acceleration and alot of other factors into consideration. It depends on the surface your driving on, your tires, engine etc.

Anyone can calculate distance driven in x time at x speed though.
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wolfy42 posted...

I'm good at all math related questions, but you have to take acceleration and alot of other factors into consideration. It depends on the surface your driving on, your tires, engine etc.

Anyone can calculate distance driven in x time at x speed though.

Yeah, which is why knowing what level of physics matters.
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If you are trying to travel 140.65 meters in 5.5 seconds, you can determine the minimum acceleration rate you would need. The fact you are making a turn complicates things as well, as it can limit your maximum speed (without sliding) and increases the tires/surface factors significantly.

Still you can come up with a decent idea of acceleration rate you would need to achieve in order to travel 140.65 meters in 5.5 seconds.

If you accelerate at 10 meters per second you would travel 5 meters in the first second, 15 in the second, 25 in the third, 35 in the fourth and 45 in the fifth. You would travel then accelerate 5 mph in the half second left, so the average would be 47.5/2 for the last .5 (basically 24 miles).

The total is 149 miles or so in 5.5 seconds. A bit more distance then you would need, but that isn't factoring in tires/surface etc. So your acceleration needs to be about 10 meters per second basically. That seems to be the only thing your missing.
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Lokarin posted...

zebatov posted...

So the time is 5.5 seconds, and the distance is 140.65m.

so yu need to go 25.52727272727272727272727 m per s

Then multiply that by however many seconds are in an hour to get m(eters?) Per hour.

25.5*60*60

Then divide that by 1000 to get kilometers per hour.
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Yellow posted...

Lokarin posted...

zebatov posted...

So the time is 5.5 seconds, and the distance is 140.65m.

so yu need to go 25.52727272727272727272727 m per s

Then multiply that by however many seconds are in an hour to get m(eters?) Per hour.

25.5*60*60

Then divide that by 1000 to get kilometers per hour.

Btw this lines up with my acceleration math above, fairly close, as your average speed would be 1/2 your max speed which was 47.5...just a bit under 25 meters per second.
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Lokarin posted...

zebatov posted...

So the time is 5.5 seconds, and the distance is 140.65m.

so yu need to go 25.52727272727272727272727 m per s

Is that true? Or joking.
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Basically I got run off the road by a tractor/trailer who pulled out from a yield sign. He is lying and saying we left both exits (140m distance) at the same time. I ended up at his diesel tank, which typically sits ten feet or so back from the front of the cab. The time comes from him being at a dead stop until the time I almost hit him (I have video but I go behind his trailer and nothing else is seen). He also admitted he was empty. If we left at the same time like he said, I don't think I would have even come near the back of his trailer, much less the middle of his cab.

I think I have the answer in other words. It would have been impossible from a dead stop, with no traction control system, in wet conditions, to go that distance while making a right turn in 5.5 seconds. That doesn't even take deceleration into account. That is foot-to-the-floor acceleration with no intent of stopping. My vehicle has 240 brake horse @ 6000rpm and weighs 4200 lbs with me included. I stopped about two inches from his diesel tank, meaning most of that 5.5 seconds was me decelerating.

The truth is I might have bee. Going 53 kilometers per hour (~32mph). The point I'm trying to make is there's no way we pulled out at the same time. He's lying to try to put blame on me as his words about me were "....had he been driving accordingly..."
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I think in general it's whoever had the yield sign in such a situation that is at fault...no matter who left first etc. I have never seen a stop with multiple yield signs that would be very confusing. If he had a yield sign and didn't yield, then he is at fault, if you had it and ended up getting run off the road, well, you should have yielded.

If it was 2 stop signs, neither saying yield, then again, it's generally the responsibility of the smaller/more maneuverable vehicle to avoid the larger one. A truck, even empty, take far more time to brake or accelerate then a smaller car.

It does not sound good for you in any instance unless the truck had a yield sign and you did not, and even then, it really is arguable since the truck takes longer to get going/stop and it's hard to prove that when he started moving you were already at the stop sign, or past it.

Video might help, but I don't think physics are going to win you anything in this case.
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It doesn't matter about the physics then? He was at a yield sign.
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I already know that. I have my class 1 license. ICBC is a government-run insurance corporation that gives to the BC government when the government overpends. They're a multi-billion dollar corporation fighting a blue-collar labourer over ~$1450 CAD. Broke my rim and (thought I) needed a tow (could have just used my spare). I'm only going for the cost of the rim and the work to fix the wheel hub, which was also bent.

Like I said, I have video from the business we were pulling out of... It just doesn't show the impact because of the angle of the camera.
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I am not an expert at traffic laws but this is my take on it.

Yield signs usually will mean whoever had the sign is responsible for an accident.

The problem though is if someone had already passed the sign, before the other party entered the picture (Arrived at their stop sign for instance).

A truck would be a prime example of this happening, since trucks take significantly longer to accelerate.

So if you have two people one has a yield sign, the other a stop sign, and both leave at the same time, the person with the yield sign will be at fault. If you have a truck though which accelerates significantly slower, that pulled up to the yield sign, saw nobody at the stop sign (yet), and started accelerating. Then another car pulled up to the stop sign, quickly braked then accelerated to try and get past the truck (we all do that), it would actually be the driver of the cars fault.

Since this is a very likely scenario, even if it didn't actually occur, it could be hard to prove that it didn't. Since a truck does not have nearly the control over it's speed or ability to stop/slow down etc, I believe the fault will still usually go to the driver of the car.

I might be wrong, but that makes the most logical sense. Don't mess with a truck basically.
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I tried to stop the guy (got in front, stopped close so he couldn't leave as he was actually trying to run) and he looked at me and said "You saw me pulling out." So right away I knew I was going to have yet another battle on ny hands if someone is going to make an idiotic statement like that.
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Ahh, cool if you have video and it shows you stopped and him stopped and both leaving at the same time (or him leaving after you), then you should be golden. You don't need video of the impact really, you just need to prove that he had a yield sign and didn't yield.

That is pretty much the crux of the issue because without that, I think blame will fall on the smaller car in most cases.
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wolfy42 posted...

I am not an expert at traffic laws but this is my take on it.

Yield signs usually will mean whoever had the sign is responsible for an accident.

The problem though is if someone had already passed the sign, before the other party entered the picture (Arrived at their stop sign for instance).

A truck would be a prime example of this happening, since trucks take significantly longer to accelerate.

So if you have two people one has a yield sign, the other a stop sign, and both leave at the same time, the person with the yield sign will be at fault. If you have a truck though which accelerates significantly slower, that pulled up to the yield sign, saw nobody at the stop sign (yet), and started accelerating. Then another car pulled up to the stop sign, quickly braked then accelerated to try and get past the truck (we all do that), it would actually be the driver of the cars fault.

Since this is a very likely scenario, even if it didn't actually occur, it could be hard to prove that it didn't. Since a truck does not have nearly the control over it's speed or ability to stop/slow down etc, I believe the fault will still usually go to the driver of the car.

I might be wrong, but that makes the most logical sense. Don't mess with a truck basically.

So this is why I want to know how fast I'd have to be going because I need to show the court that I was 100% already on the through-road before he even started going.
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wolfy42 posted...

Ahh, cool if you have video and it shows you stopped and him stopped and both leaving at the same time (or him leaving after you), then you should be golden. You don't need video of the impact really, you just need to prove that he had a yield sign and didn't yield.

That is pretty much the crux of the issue because without that, I think blame will fall on the smaller car in most cases.

As long as you know that an impact happened, it should be fine. His vehicle should still be damaged on the spot, so the position shouldn't really matter that you verified it.
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Also if you have video of him trying to leave afterwards and you stopping him, that would be great as well:)
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I don't have that video. It cuts off because of the angle. It shows the truck pulling out then me driving onto screen and going behind his trailer. The guy also hit me/pushed me the truck when I was walking back to my SUV but I can't prove that at all.
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Well, everything you have said points to it being possible for you to go from a dead stop to that full distance (heck even more) and also, that doesn't prove you didn't just drive through the stop sign etc, which could mean you were going 40+ mph the whole time etc.

Video is more important here, math isn't going to work as it's obviously possible for you to accelerate faster then a truck. He could have been almost half the distance probably and you could have ended up where you where (just based on size/acceleration alone).

The reason we all don't want to be stuck behind trucks in such situations is how slow they accelerate.

You might be able to do the reverse (prove a truck could not get X distance in X time even empty based on acceleration rate etc), but proving that you couldn't? I mean, your not looking at sports car level acceleration here, many cars could have left well after the truck and still gotten past it.
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You have to factor in that was I slowing down, not speeding up. I know it's plausible if I hammered the gas in ideal conditions and stayed on it, but I was on the brakes. Otherwise I would have hit his diesel tank, there would have been more than $1400 damage to my vehicle, probably $2000 or more to his, plus an environmental with diesel everywhere.

The speed to cover 140m in 5.5 seconds was about 55mph Lokarin said. That's forty or so over the speed limit. And that's the whole 140m distance. I was stopped and you can't just start at 55mph.
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Thanks for the help though, people.
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