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Alright, not much room up there, You have TWO of the EXACT same cars. Say they are going 100 miles. They start at the EXACT same time, same place, same road conditions, same everything. Nothing is diffent except the speeds. One is going 50 miles and hour, the other 80 miles an hour. Which would be more gas efficient? Its obvious the one going 50mph would use less gas, saving you money, but wouldnt it be about the same because while the other one is already at its destination, and the other is still going. Which would be better, if so why do people go as fast as they do on the interstate?

2007-01-12 08:12:39 · 16 answers · asked by nimeskern47 1 in Cars & Transportation Other - Cars & Transportation

16 answers

the faster you go, the more gas you burn, period. it is more cost efficient to slow down.

2007-01-12 08:16:09 · answer #1 · answered by Terry M 3 · 0 1

You seem be asking two different things out of the same problem. The car going 50 would get better gas mileage but the car going 80 will allow you to more time at the destination. If you have a lot to get accomplished at the destination and a limited amount of time to do it and it's worth the cost for the difference in gas used and the possibility of getting a ticket to get what you need done, then the 80 car is more efficient. If you have a lot of time the 50 car is more efficient. It all depends on peoples perceptions. If people think they have no time and a lot to do, they will generally drive fast.

2007-01-13 07:52:26 · answer #2 · answered by max69442 1 · 0 0

I don't think it's accurate to say "obvious the one going 50mph would use less gas"... because as you point out, the 50mph car still has to keep going. Taken to extremes even more, if you have two identical cars, one going 80 mph and one going 20 mph, the one going 20 mph would be way more expensive for the same distance, because your engine is not running optimally. I think the optimal speed is dependent on the car, and remember that acceleration is different than speed. Acceleration is what takes a lot of gas, but maintaining a speed like 60 mph usually doesn't take quite as much gas. On my car, I am going about 75 or 80 mph, but on other cars, going 50 might be optimal and going 80 might be more expensive.

2007-01-12 08:18:52 · answer #3 · answered by Lowa 5 · 1 0

There is not a precise answer to your question without more information about the fuel economy of that car at a given speed. But in general, with current autos, I would guess that you will probably have more fuel economy at 50mph.

You have to keep applying gas because of friction and air resistance. The drag due to air resistance increases with the square of velocity, so at 80 mph, you have a larger amount of force that is slowing you down. Doing some math, at 80mph, you would have 2.56 times as much drag. This squared relationship is what makes going faster so costly.

But if there were no air resistance, and no friction, and you were on a very long journey, then yes, going faster could save gas, because you would have to use some gas to keep the engine running (and to keep the radio running, air conditioning, etc.).

People go as fast as they do when they're on the interstate because as much as those people complain about high gas prices, they're probably too impatient to go any slower.

2007-01-12 08:42:18 · answer #4 · answered by cryp3 2 · 0 0

The answer is not mathematical but psychological. People tend to hurry through tasks like driving because they left home late, or some other event delayed them and they think they can make up the lost time on the road. Rarely does efficiency or cost come to play. During the last fuel shortage, I slowed down and watched my gas consumption drop. However it was a temporary bout of sanity. I soon saw the prices drop and the old habits of driving 80 mph took over again. Also I would like to add that the manufacturers have geared the cars and trucks we drive to be capable of speeds way in excess of safety. With over drive I can run 70 mph at 2500 rpm. This means my engine that red lines at 6000 RPM has the potential to take me down the freeway at 150+ mph. Go figure.....

2007-01-12 08:27:51 · answer #5 · answered by yes_its_me 7 · 0 0

Calculate it out. Say both cars got 25 mpg. going 100 miles at 50mph it would take the car 4 gallons in gas.

Now, you lose about 5% efficiency for every 10 miles over 50. for simplicity's sake, Let's say that at 80 mph you only get 21mpg. you'll use about 4.7 gallons to go the 100 miles. You're beating yourself out of about $2.10 at $3 a gallon

Doing 50mph you make the trip in 2 hours. At 80 you make the trip in an 1.25 hours. Hhmmmm. That 45 minutes only costs you $2.10. Not bad when you count in fatigue.

People travel so fast because in this case, it's well worth the $2.10 to get somewhere and relax 45 minutes earlier than the next guy.

2007-01-12 08:23:16 · answer #6 · answered by Lemar J 6 · 1 0

Well I'm only 15. But in Drivers Education my teacher showed us a diagram that said "If 2 cars are going the same distance in the same conditions, but one is going the speed limit and the other is going 10mph faster, the one going the speed limit will use less gas because it will get all green lights the entire trip. The one going faster will get all reds. This is because all of the stop lights are synchronized to the speed limit." I don't know if this applies in other states. But that's how it is in Florida ;-)

I hope that helps.

2007-01-12 08:24:00 · answer #7 · answered by Semper Paratus 1 · 1 0

It will all depend on the difference in fuel economy between 50 mph and 80 mph. Could be a great math question in the classroom.

2007-01-12 08:16:04 · answer #8 · answered by shopalldeals 1 · 0 0

In a hundred miles ,you probably wouldn't notice the difference.The greater the speed,the greater the friction.More potential energy is needed to go the same distance

2007-01-12 08:18:17 · answer #9 · answered by boatworker 4 · 0 0

50 because right when you hit 60 your gas mileage goes down 59 great gas mileage they go fast because the other people are going fast and they're going fast because others are going fast and so on (and also so the big *** 18 wheelers do run them over)

2007-01-12 08:19:27 · answer #10 · answered by Anonymous · 0 1

The government has already figured his out for you. It is why we have speed limits; to save fuel, even if they would like for us to believe it is to save lives.

2007-01-12 08:19:48 · answer #11 · answered by cogs 2 · 0 0

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