I realize that's how it is. My question is why.

Adrenaline does many things, among which is it mobilises energy sources. This basically means that your muscles get much more access to simple sugar to burn during physical activity. Before, sugar (glucose) was stored away as glycogen, a more compact, way bigger molecule. Imagine this as having to build something with legos in a rush: you have many pieces stored in tall simple towers, but since you are in a hurry you will quickly destroy the towers in order to have a lot of pieces laying around so that you just have to pick them up.

When you destroy the towers (glycogen) that sends a message of fatigue to the brain, both general (you need to rest) and specific for the muscle (you find it harder to move that specific muscle). This happens even if adrenaline is not involved, but adrenaline makes it that most towers in every muscle get destroyed, so you will feel very fatigued. Adrenaline blocked the feeling of fatigue, so you felt it only when it got out of your bloodstream.

This is why you felt "the crash". But why your boyfriend didn't?

Different factors.

• he might have had less adrenaline around, because of past experiences that made him less "scared" of high speeds
• he might have had the same level of adrenaline, but less responsive receptor (i very much doubt this, but i don't feel like excluding it) and that would be completely genetically determined
• he might have had more towers. That depends on how much one eats and is fit, on age and, most importantly, on gender. Assuming your boyfriend is genetically male and you are genetically woman this i the biggest reason in my opinion. Males have, on average, bigger muscles and a more efficient muscle metabolism than females.

It's also possible that females evolutionarily developed a much stronger reaction to adrenaline, because it would make sense to think that when in danger they would have had to also protect children, traditionally in their care. This would justify a much much stronger reaction. But it's just a possibility.

There might be other reasons i am not aware of that could be more decisive in explaining the phenomenon, but this is my understanding of it

Liquid is a state of mater. Fluid is a state of movement. Not all fluids are liquid and not all liquids are fluid.

Mileage on a car is really more an indicator of wear than "age" of the car. The car does not have the ability to log "city" vs. "highway" mileage. So you, the buyer, need to look at the age of the car and the number of miles on it and decide for yourself how much wear you think the car has.

If the car is 5 years old and has 150,000 miles on it, obviously those are highway miles because the highway is really the only way to put 30,000 miles on a car in a year. On the other hand, a 5 year old car that has maybe 60,000 miles might have spent all of its time in city traffic. Taken in combination with the overall condition of the car's interior, etc. you can get a pretty good idea of how it was used and how worn it is.

Gas internal combustion engines are typically 18-23% efficient in terms of mechanical energy out vs chemical potential energy in. High performance and forced induction engines can to a little better than that but not by much. You lose a lot of energy through heat, sound, vibration amongst other things. Also emissions really damp efficiency but are obviously important. It would be cool to see a car manufacturer build the most efficient, light and not overpowered car possible to see just how much they could stretch the mileage.

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There is. It's called "going to the mechanic to check if the car is in a condition as advertised".

Mileage is a fairly reliable measure for the expected state of the engine/drivetrain of the car. The parts that, if worn out, usually get the car scrapped, because replacing them would be as expensive as buying a working car.

I would love to hear from someone who'd replace a broken driveshaft or a wrecked engine on a Toyota Corolla.

>why there isn't a metric to distinguish between used cars that have been driven in an urban setting as opposed to highway cars where there is clearly a larger wear and tear Factor due to the fact that the miles placed on them are more strenuous miles on the car as opposed to a clean highway mile that affects more than just the engine output, we have it more gas mileage

Both - among others - are important and entirely separate metrics. Knowing the circumstances under which a car was driven is pointless without knowing the mileage. Knowing the mileage is pointless without any other data. A car's literal age is yet another important metric that has nothing to do with its mileage but is determined by looking at its build year.

There are dozens of other things that are important for determining and putting into context the condition of a used car. And any salesperson will provide you with the necessary details, not just the mileage.

Baseboard: Electricheater with no fan located wher ethe wall meets the floor. Cold air is warmed and rises up the walls to the ceiling. Most houses with these will have ceiling fans to blow the warm air down in the center of the room where it cools and spreads back to the heaters. Not very efficient and you lose the ability to place a couch or bed next to that wall.

A furnace is like your oven. It burns a fuel, could be natural gas, propane, or fuel oil. A fan forces the warm air into the room, or into ducts that lead to vents in each room (this would also be central heating).

Central heatimg... the heater is in one location, normally the canter of the building with ducts leading to rooms and hallways. Cooling that works the same way is central cooling.

A window unit would be those AC units mounted in a wi down, and sometimes a hole in the wall, though there are dedicated wall units too, some of those also have a heater. Often used to just cool a room, or a small house at most.

Radiators are old school and suck. There is a large radiator, like what's in a car or AIO in a P , that has your hot pumped through it. The heat from the hot water going through those pipes warms the area. Larger buildings will have a boiler dedicated to heating water for this, and this is usually better. It can be heated to a higher temp si ce there's no danger of your turning on your hot water faucet and scalding yourself, and since it's in a sealed loop there won't be any loss of heat because you're taking a shower like Wil happen with one that uses shared hot water.... those really suck. Ok in summer or extremely mild winters, but are terrible when it's on the 30s or below. Bad in the 40s even.

A heat pump is based on a Peltier I believe. Or at least works in a similar way. It takes the heat from.k e location and sends it to another. This can be used to her or cool your home. Usually not used in extremely cold places and where it does get cold it wil.often have another heater as a back up if it can't maintain the temperature.

My first "new" car was an '86 Pontiac Acadian, 2 door. 1.6L inline 4 cyl with an automatic transmission that I quite literally drove like a go-kart. Would regularly take corners at speed by throwing the shift lever into "L", locking up the rear wheels, allowing me to drift into the turn, then back into "D" and nail the gas pedal to the floor.

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Only ever popped the bead on the rear tires twice. Fortunately, refilling them also reseated the bead.

In the absence of a better aggregate indicator, the mileage is a good first approximation for how used a car is.

Of course it is no replacement for a service history and a good pre-purchase inspection.

The short answer is that the technology of the odometer pre-dates any ability to track the speed/ torque usage of the vehicle. As such, the “miles only” odometer is the de facto standard. Modern cars could have more meaningful metrics, but there is no requirement to add such a thing, so manufacturers don’t bother.

This is an amazing analogy

Since no one else has talked about wine:

Its a common misnomer that more expensive wine tastes better. In my experience (been working with wine for about 20 years) most newer or infrequent wine drinkers prefer cheaper, fruitier and sweeter tasting wine. More expensive wines tend to be aged in various types of barrels that alter the profile of the wine. They tend to be drier, oaky, and more secondary/tertiary flavor notes (ie wood, spice, vanilla, mushroom etc). Many inexperience wine drinkers do not have a refined enough palette to be able to pick out the complexity of many more expensive wines.

Except for the fact that the US is literally one of two countries that haven't adopted metric.

But yeah, just like any other country

Yup. We would be very concerned until that glucose came back 106. Then we chuck a water bottle at you and laugh you out the door.

People forget just how much the US itself has in the way of ruins, old tunnel systems, shelters, etc. The Manhattan Project was able to run beneath a major city like Chicago because of the sheer scope of modern-ish ruins. It's also analogous to the catacombs of Paris, someday the tube system will be a ruin just like that, and probably a new city will be built on those ruins.

Much of the increased fuel efficiency came from the addition of electronic modules to control nearly every system in the automobile… engine control, fuel delivery, transmission control, power steering control, etc, etc, etc. Each of these advancements have added a few percent to the overall efficiency.

For example, power steering used to be accomplished by a hydraulic power steering pump on the serpentine belt on the engine. When you were driving on the freeway at 75mph, you were barely turning the steering wheel. Most of the power to drive the pump was unused and wasted. Electronic Power Steering (EPS) instead senses the need and then controls motors as required, providing roughly 3% overall fuel savings.

This same approach has been applied to every system within vehicles. Rather than add weight, electronics increase the fuel efficiency while reducing weight. For example, the EPS modules and motors weigh less than the hydraulic power steering pump, hoses and hydraulics that used to be driven by the serpentine belt.

>nobody is getting accords for power/speed

True, but speed isn't the only reason to have more power. There is safety measure, but also luxuries. I like my divertissement screen, the GPS, the collision detection, the heating seat, etc. All of this mean more not only more weight to carry around, but also more electricity that come from the engine.

I also like to have a responsive car and a smooth acceleration, and for that you need more power. You don't really need to put the engine to the max to reach illegal speed on the road, but a more powerful engine change drastically how driving the car at low speed feel.

>I want that more efficient engine in lighter weight body to maximize efficiency

And there is other models that do just that. That said, those models are a lot less popular in North American compared to Europe so there isn't as much model available. Manufacturers sell what the market want.

Bro forgot to read rule 4

2/3 of the energy of an average ICE is lost as heat and noise. The main limiting factor is the size constraints of ICE don't allow it to use that heat the same way a power plant can, hence why round trip fuel /carbon efficiency of BEVs are so good even when the electricity comes from fossil fuels.

A poster at my gym says to drink 1ml of water for every calorie of food you eat. I don't know if it's based on any science, but it sounds pretty reasonable. Better than 3l a day no matter if you're 5 feet tall or 6 foot 5.

Some cars do gain a few MPG when you go for lower / base trims. I know the Kia Niro and Hyundai Ioniq (not Ioniq 5) do.

1990 Toyota Tercel checks the boxes too. It felt like I was driving a go cart with windows. Had to kick off the AC to get to highway speed fast enough.

That's interesting, I'll have to read up on that. This limit is for purely thermal engines that run on a hot and cold heat transfer cycle. So I can imagine something hybrid would do better, but I'd be willing to bet that if we took a close enough look at that engine we'd find the thermal only part of the engine being under 50% efficient, and the rest was boosted by a different system.