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Homework Help: Rocket experiment: conservation of energy

  1. Oct 26, 2006 #1
    Hi i posted a question about the rocket experiment i did at school a few days ago but i just need some clarifications on some things.
    I know that when a rocket is launched, not all kinetic energy is transferred to potential energy as it travels. That's why when i used formulas to figure out the energies and figured out the maximum height that was reached, was totally different from the actual height. Some of u guys helped me out by saying that the differnence in height is caused by losses of energy, friction between rocket and the launch pad, and wind.
    I don't quite understand though, how energy would be lost because I thought energy is never lost. Does any of this have to do with the burning of the engine? and how would wind cause the calculation of the max. height to be so different from the actual height?
  2. jcsd
  3. Oct 26, 2006 #2


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    I didn't see your prior post, however, generally speaking, energy can be lost, gained, or conserved, depending on the work done on the system. If a block is at rest on a frictionless table, with no energy, and you push it, it gains energy because of the work you must do to get it moving. The same block might then lose energy when it runs into a surface with friction. Or keep the same energy when only gravity is involved (like if it just fell off the table to the floor, energy would be conserved. Actually, when you consider that energy is required by a person when he pushes the block (chemical energy), or that work done by friction is converted to heat energy (the table gets hotter), in that sense, all total energy is conserved in each case. Regarding the wind force, that might be an air resistance force that slows the flight, and can create tremendous heat.
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