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Automotive Intermittent contact in rolling friction

  1. Jul 6, 2012 #1
    hey i had a bizarre thought, what if there is a road made with a very smooth friction less surface and a normal asphalt road, arranged alternatively, such that , half the time spend by the tire in one rotation is placed on the smooth side and the other half on the rough side, such that the tire completely slips on the smooth side,the vehicle is in linear motion which is generated by the rolling action of the wheels, my question is , will such system deliver the same amount of power for propulsion compared to a conventional tire road sys., becoz i think that when the wheel will spin on the smooth portion it will increase its angular momentum(due to slipping), and thus when it will hit the ground with friction, it will deliver more thrust, in less time, and it will slip(angular) and glide(linear) for the next part of the surface, is such system practically possible...?
  2. jcsd
  3. Jul 6, 2012 #2


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    I can see a lot of problems with that. Not the least of those is that without a limited-slip differential that car isn't going to move at all. Then there is the absolute hell that will be played with the steering and braking.
  4. Jul 6, 2012 #3

    jack action

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    You cannot create energy out of nothing. At best, the energy that you will recover from the wheel momentum will be exactly the same as the one you lost in traction on the slippery surface (and that was Ā«convertedĀ» in momentum).

    But because spinning will create friction that will create heat losses, you will never recover completely that lost energy (or power).
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