Question for the scientists....

Ok people heres a far out one...please no flames back at me..my head is always in the clouds...im a back shop tinkerer and inventor. Suppose you had a car that weighs, lets say 2500lbs. Now lets say that you had a special electrical machine that when activated, pushed up on underneath of car subtracting 800lbs from the car sitting on a scale. it now weighs 1700 lbs sitting on scale. you havent taken anything off of car, only "activated" the machine. Now you take that car to the race track. Would you be running at 2500 pounds mass? or the new 1700? Would it take less horsepower to get you going? the weight subtraction is only north and south of the car in referance when sitting on a scale. In forward momentum would the engine see 2500lbs mass or 1700lbs? Dont kill me guys...squinting...;-)

RE: Question for the scientists....

Sounds like someone stopped at the local tavern after work.




This would be possible actually, if your referring to a device that worked like the electromagnetic high spped trains. However, it isnt the issue of weight, the weight will remain constant. Its a matter of friction drag on the surface. the more downward pressure there is the more power it takes to move it forward. Thus, if you effectively floatd the car a bit, you would notice increased performance and higher MPG but lower traction.


Now I need a drink.

RE: Question for the scientists....

I'm not thinking all that well (not that I ever do, but 6 hours of work/homework will do it) but I'm thinking WTF are you talking about.

Your still going to have the same weight/mass pushing down on the car. It has 4 contact points, 1 on each tire. As long as those points are still in contact with the ground, or in this case the scale, the vehicle will weigh the same.

Secondly, as noted in the above post, what about the drag/friction? Your going to need more power to overcome this?

RE: Question for the scientists....

The friction you would be worried about would be the hubs the wheels are on. Then engine would see the same mass b/c of the potential energy reserved in the mass of the car. (or so I think) The engine still has to move the car from a sitting postition and moving the same mass is going to take the same power.

Take for example the space shuttle in space.

The space shuttle has no weight at all right. You would think that you could accellerate exponentially but you cant because of the mass of the shuttle.

My answer would be that the difference wound be none to the engine. http://users3.ev1.net/~acashiola/ot/squint.gif

RE: Question for the scientists....

the context is similar to that of a hovercraft, which doesnt totally hover, but just reduces the weight effect. it still weighs the same, but the weight is being counteracted by the downward thrust to some extent.

RE: Question for the scientists....

I loved physics till the hot teacher was fired half way back through the year back in high school. My grade went from an A- to a C.

RE: Question for the scientists....

Mycophiles is right

Weight does not equal mass

Mass is mass no matter what happens to gravity.

RE: Question for the scientists....

/me bites his tongue

RE: Question for the scientists....

haha thats what im thinking..the "mass" of car from stop to go, would remain the same....just wondering if it would be different having less weight. ok we can end this one now...just another wierd post eh? lol