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  1. Lukeblackhill

    Question regarding pressure and energy

    If you apply a force in a body of volume V, in its area surface A, the body experiences a pressure P=F.A that acts in it in order to peform one or more of this actions, such as a. expanding, b.contracting, c. deforming, d.heating, etc. In all cases, the P.V = W, that is the work done on the...
  2. Lukeblackhill

    Symmetries and Conservation Laws

    I've been caught by a quite interesting statement of Berkeley physics Course Vol.1 (Chap. 5), that says "In the physical world there exist a number of conservation laws, some exact and some approximate. A conservation law is usually the consequence of some underlying symmetry in the universe."...
  3. Lukeblackhill

    Reduce Kinetic Energy Losses when Two Objects Collide

    I'll try the super-balls, @anorlunda Thank you!
  4. Lukeblackhill

    Measuring Velocity

    The idea of the camera is good, @Orodruin. I'll try that. I will also give a look about this Stroboscope. Thank you.
  5. Lukeblackhill

    Reduce Kinetic Energy Losses when Two Objects Collide

    I'd like to know which methods I could use to reduce the loss of kinetic energy when two iron balls collide, or when a plastic ball collides with the floor after a free fall. I have tried to cover the floor with a fabric that would make it more elastic, but it had a small effect (if it hat...
  6. Lukeblackhill

    Measuring Velocity

    Morning! I was performing some experiments about impulse and conservation of mechanical energy, and for that I was looking to good ways of measuring the velocity of a sphere under the action of a force. In free fall, having the height H it was falling along, I have used the formula v =...
  7. Lukeblackhill

    Galileo's Experiment with an Inclined Plane

    Morning mates, I've peformed Galileo's experiment with inclined planes, using a ramp of 88cm (divided in 4 parts of 22cm), inclined by a height on the right-edge of 4cm. I've measured the following, 1/4 of the ramp (22cm): 1.75s (error of 0.1s) 1/2 of the ramp (44cm): 2.70s (error of 0.1s) 3/4...
  8. Lukeblackhill

    Energy required to accelerate itself

    @greypilgrim, as our friend PeroK said, if you consider the car itself, You'll always be talking about a frame at rest. The car applies the same force (and by consequence, the same energy) than any other external object would, for the law doesn't consider sources, but the frame of reference. So...
  9. Lukeblackhill

    Problem with the Definition of work

    I may be wrong, but on the treatment of the 2nd law, (at least for non-relativistic systems) we have a vector as the product of a vector by a scalar F=ma. In the treatment of work, we have the scalar product of two vectors, resulting in a scalar F.d = W. I don't know if such consideration has...