# Why can't you power a car using its own movement?

Asked by Lost_World (1231) June 29th, 2008 from iPhone

Why can’t you put a wind mill on a electric car and use the wind that goes past the car to spin the wind mill and make power for the car?

Sorry for the spelling I’m on my iPhone.

Observing members: 0 Composing members: 0

Also why can’t we power our cuntry with wind mills, wave power and water weels.

Every one I know says it will never work, but only 6 mill ppl it could work.

Lost_World (1231)

Jesus man.

Spargett (5395)

The car will inevitably use more energy fighting the extra drag created by the windmill than the windmill will feed back into the system. If this idea worked, then perpetual motion machines would become a reality. Sadly, it won’t.

Harp (19179)

This reminds of the episode of the Simpsons where Lisa gets board and invents a perpetual motion machine and Homers response was “In this house we obey the laws of physics”

Lightlyseared (34104)

It is due to the Second Law of Thermodynamics. Basically entropy is always increasing in a system. Mean you always have energy wasted to heat or other lossy phenomena.

mvgolden (824)

Although I know it is impossible to create/destroy energy and that a lot of enery is lost via heat/sound with a moving object like a car, but instead of making extra drag by putting the wind turbine on the outside how would putting a ‘tube’ through a car and having a turbine in that affect the car, it’s movement, drag, fuel consumption, how much energy could be created from the mini turbine etc. I don’t know how it would affect it seeing as I’ve never seen it done. I think I’m just babbling here. If anyone understands please answer hehe.

Skyrail (1700)

I have thought that it seems like a waste to use energy to make a car move and make a car stop. Why can’t they develop brakes that capture the kinetic energy rather than just lose it to friction, etc.?

phoenyx (7388)

It’s true that you can never get 100% of the energy back, you can try to reclaim some energy in a few places. For example, Regenerative Brakes can generate some electricity whenever you hit the brakes. This is useful because it is reclaiming energy that would normally be lost as heat (friction) from the brake pads.

Any kind of wind turbine probably wouldn’t work as it produce a constant additional drag which would force you to waste more energy in the form of fuel to compensate for the drag. It would be a net loss of energy.

xyzzy (661)

xyzzy: Thanks for that link; very interesting.

phoenyx (7388)

Perpetual motion violates thermodynamic law. You could get a ticket.

AstroChuck (37560)

if you violate a thermodynamic law and only get a ticket you probably have to consider your self lucky.

Lightlyseared (34104)

I happen to be a big fan of entropy, so I don’t ever plan on violating it.
But I could if I wanted to, though.

AstroChuck (37560)

You can’t get without giving. In theory, that’s also how Christmas works.

Ho ho ho

Knotmyday (7511)

LOLs @Lightlyseared, awesome, GA

or