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Homework Help: Conservation of Energy (physics)

  1. Mar 3, 2009 #1
    1. A bowling ball is hanging by a wire from the ceiling, and is swinging back and forth...

    2. At what position(s) does it have the least speed?, greatest speed?, least kinetic energy and why?, greatest kinetic energy and why?, greatest mechanical energy and why?

    3. The attempt at a solution I'm not sure how to go about getting to the answer. Is it just a conceptual quesition, or do I need to consider some sort of equation?
  2. jcsd
  3. Mar 3, 2009 #2
    You are right, this is a conceptual question.

    Try to think about the energy at different points in the motion. What types of energy will be present when the bowl is at the very top of its swing? What happens to this energy as the ball progresses?
  4. Mar 3, 2009 #3
    Well, I've already figured that the least potential energy when the ball is straight down, and the most potential energy when the ball is at the highest point, but how do you figure in the speed (velocity) from this? Is it that the ball will be moving the fastest between the middle point and the high point, because at the top it would be approaching 0 m/s and at the bottom it would be approaching 0 m/s? And how does mechanical energy work in this example?
  5. Mar 3, 2009 #4
    Why would it be approaching 0m/s at the bottom? It has the most kinetic energy when it has the least potential and velocity is related to kinetic energy, what's the hang up?
  6. Mar 3, 2009 #5
    I don't know. I guess it wouldn't... it would be picking up speed as it fell and then slowing as it goes up, so I guess the speed would be the greatest at the bottom.
  7. Mar 3, 2009 #6
    I figured out all of it except the mechanical energy? How does this work?
  8. Mar 3, 2009 #7
    mechanical energy = kinetic+potential, what can you say about this quantity?
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