Is the Hummer "greener" than the Prius?

You're forgetting externalities. While a useful concept, nowadays they're typically abused by environmentalists and urban planners to arbitrarily assign costs to things they don't like. They do this even when the magnitude of the claimed externality is so enormous that the financial burden (which has to be paid by someone, even with an externality) could not possibly be missed, and yet it is.

Apparently Hummer fans have learned to abuse them too.

The Peugeot 504 that I learned to drive on has a 60 HP or so engine. It has a top speed of around 80 or 85 mph.

Drag increases as the cube of the speed of the vehicle (so it takes 8 times as much power to keep a car going at twice the speed - the cube is

2 x 2 x 2). So, if it take 10 HP to make a car go 40 mph, it will take about 80 HP to go 80 mph.

So I think 65 HP is a pretty reasonable figure.

Jeff

Same deal there, what's the gearing like? The engine has to be in a good part of the powerband to accelerate.

And what year Peugeot was that? I thought they had something more like

85hp. The 74 seems to have had 73hp. Ooh, the 1980 convertible had 110hp and would achieve 110mph! And it's a very nice-looking car.

I thought drag was proportional to the square. I'm fairly certain of this but the physicist child is not here to ask. I think there are some linear components, too.

Ah. Here we go:

Of course, that's your aerodynamic drag only but I don't think there's any cube function in the other drag you'll encounter.

It was '74 504 diesel.

says it was 65 HP. I recognize the model number XD90, so I think it's correct. I have also seen specs that show a 1.9 liter engine with 59 HP and 2.3 liter engine and 70 HP, but I think those were for other countries for the same year.

You're correct. I almost was. The force goes up as the square, but the power needed to overcome the force goes up as the cube.

The drag is a force. The force that the engine exerts to overcome the drag is the square of the speed. So the force and work that a car needs exert goes up as the square of the speed. However, if you double the speed you increase the power you need not by four times, but by eight times, because you're doing four times as much work in half the time (power = work / time).

Go down to the section called power. It's confusing.

The rest I wrote is correct.

I think you mean "calculations are so much easier in SI" !

What's a slug btw ?

Graham

Wrong by nearly 3:1.

Graham

What's so useful about a system that uses multiples of 3, 8, 12, 16 etc... between adjacent units ?

Graham

In message news:4668312b$0$16394$ snipped-for-privacy@free.teranews.com, DH sprach forth the following:

Hey dumbass - don't you realize that "99papers" in the link indicates the YEAR THIS PAPER was written? How many Priuses were produced in 1999?

Your link, your brain, your life: all obsolete.

1) The entire country is surveyed in those units 2) There are a plethora of useful integer-valued approximations.

How so? I've seen a couple Hummers flipped onto their sides or top after altercations with cars (which remained upright).

Yes, and I bet the Hummer wasn't crushed like a tin can either. Would you really want to be rammed by a truck while in a Prius? Think before you answer.

Exactly. You can't.

Graham

They probably picked it because it's readily available and, at 12V, it can run all the car's accessories. And perhaps a charge leaks off it slwoer than off a NiMH.

Suffering from reading comprehension problems?

Toyota's engineers could.

Idiot.

I would rather be in the Hummer if the Hummer is doing the ramming.

My wife saw a Hummer rammed by a relatively small car a couple of years back and the Hummer flipped over onto it's top. The people in the car faired better in that scenario. So I guess the answer is "it depends".

Not to mention that Hummers are more likely to flip over if they go off the side of the highway or in high-speed maneuvers.

Jeff

Depends on what your wife meant by "small car". Either way, I think I would take my chances with the Hummer.

How fast was the small car going? A Mini Cooper doing 100mph can do a lot of damage, equal to or greater than a full sized car doing only 20. E=MCsquared.

E = MC^2 (E = Energy, M = mass of the object converted to energy, C = the speed of light in a vacuum, ^ 2 means squared) means that matter can be converted to energy and vice versa. This equation is only relevant here if either the Mini Cooper is blows up in an atomic explosion. Last I check, Mini Coopers are not made of uranium.

The relevant equation is E = 0.5 MV^2, where the kinetic energy E = the mass of the object M, and V = the velocity of the object.

Jeff