Prius 101 for the Physics Syncophant

I think what you are missing is wind resistance. The faster you go the more of your fuel is spent just pushing through the air. At lower speeds it's less visible.

So while the Prius EV might be good enough to lift your car those meters it also needs to push a lot of air out of it's way.

 

Managing your climb rate to deplete the battery to maybe three
bars by the top of your ascent should actually improve mileage
overall, because that gives you more capacity to store some of the
energy coming back down. But no, you shouldn't feel like you have
to totally punch it on the way up, even though air resistance at
70 kph is still a relatively minor factor. [kph, not mph...]
.
The ICE is actually at its best efficiency between 15 and 35+ kw
output -- a rather flat curve, in fact. Have a gander at
http://techno-fandom.org/~hobbit/cars/prius-curves.gif
and think about adding a tach as a guide to how much you're
requesting. I don't think crawling over mountains is a contributor
to low mileage so much as just loafing along at medium speeds
without letting the ICE shut down is. Thus, pulse-n-glide.
.
_H*

 

A flaw in your logic is that the relationship between power and speed is exponential, not linear. Doubling the speed requires 2 to the tooth more power, not just double.

 

I admit that I've forgot most of my physics which I was pretty good at back in College (never gotten less than 95% on exams B) ). I think you're missing a few points here in your calculation.

1. You're mixing up potential energy with electrical energy. Electrical energy is first converted into mechanical energy, then stored as potential energy when climbing up hills. Of course, in the process, energy is lost due to friction and heat.

2. When coming down hill, the reverse happens. But still there's lost of energy.

With that said, I'm no expert in what's the best way to drive through hills, but I tend to agree that using the battery on a up hill as much as possible to leave room for charge on the down hill may give you better results.

 

No. As long as his speed is constant (beginning to end) there is no change to his kinetic energy.

Yes. You are bad at physics.
1350 kg * 1 meter/second * 9.8 Newtons/kg = 13230 Joules/second = 13.23 kw

 

Hey, I know ABSOULTELY nothing about Physics, but I am from Albuquerque and know that stretch of road too well. Just went to my local (Santa Cruz, CA) dealership to get on the list for an 06.... :huh:

 

I am also in Albuquerque and live off of Tramway & Copper. I can't really help with any real world experience yet though because I am still on a waiting list.

Scott

 

Actually, you should try to go up the hill on an empty battery. A lot of fuel is wasted hauling all those extra electrons up the hill.

 

Mass is defined in such a way that it is equal to the weight on Earth.

When the interplanetary Prius arrives, let me know. For that, I'll pay over MSRP.

 

Nope. (Well, "sort of" if you are not an engineer.)
Kilogram is a unit of mass.
Newton is a unit of force or weight (i.e. gravity).
The weight of 1kg under the gravitational attraction of the Earth is 9.8 N (Newtons).
So the weight (downward force) of a Prius is actually 13230 Newtons (although lay people do not generally use Newtons).
The power required to raise a mass of 1 kg by 1 meter is 9.8 Joules.
To do so, repeatedly, at the rate of 1 m/s requires a power of 9.8 Watts.
To do this for a Prius with a mass of 1350 kg requires 13.23kW.

 

It is reporting the vehicle's mass.
The average man-on-the-street does not differentiate between the mass of an object and its weight and so, generally uses the terms interchangeably.
Marketers use the terms that the average man-on-the-street will understand, in this case weight and kilogram.
It's not correct but you understood what they meant.

 

Probably because it's pretty much the same "on-the-street."

 

They are very different.
It's just that the man-on-the-street doesn't know (or generally need to know) what the word "mass" really means.

Mass is an abstraction, the resistance of a thing to having its momentum changed.
Weight is a force and the force of gravity is a tangible thing.

When the average man-on-the-street holds an object of 1kg in his hand, he feels its weight (~2.2lb or 9.8N) and calls its weight a kilogram.
It's considered appropriate to equate the two in ordinary day-to-day situations but it's not correct to do so in physical equations.