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Potential Energy of a baseball

  1. Oct 12, 2011 #1

    1. In a baseball game where does the ball have the most potential energy?
    A. In the hand of the pitcher.
    B. When it makes contact with the bat.
    C. Top of a pop fly.
    D. When it’s caught in the out felid.

    2. Relevant equations

    3. The attempt at a solution
    I believe the answer is either B or C.

    any help?
  2. jcsd
  3. Oct 12, 2011 #2


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    I like your thinking - especially if we believe that elastic energy is stored in a squashed ball, but I don't think baseballs are like that - if you drop one, it does not bounce very well.

    If it is Gravitational Potential energy you are looking for - think about how you increase Grav. Potential Energy.
  4. Oct 12, 2011 #3
    The question only asks for Potential Energy, not Grav. Potential Energy...which is why I believe it would have the most potential energy when it is struck by the bat.
  5. Oct 12, 2011 #4


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    What about all the work the bat is doing on the ball? Force x distance and all that.

    EDIT: what is the actual trajectory of a pop fly? Genuine question from a non-baseball playing country.
  6. Oct 12, 2011 #5
    I feel like the bat is exerting a lot of force on the ball, giving it a lot of potential energy.

    Pop flies are (generally) slowly moving balls that simply go up in the air and fall back down, of course.

    But I feel that even if you hit a pop fly, the ball has more PE when it is hit by the bat than when the ball is at the top of its cycle.
  7. Oct 12, 2011 #6
    that is a tough one because it also depends on the bat, aluminum ones flex and compress easily while the wooden ones do not. It could be when the bat hits the ball and compresses if it is a wooden bat. Yet otherwise i would say at the top of the pop fly, because it couldn't be in the pitchers hands or in the outfielders, because neither can produce the same distance as hitting the ball with a bat.
  8. Oct 12, 2011 #7
    For A, the ball has almost no energy, its all in the pitched.
    Same with D, the energy has been dispersed.

    For B, the potential energy is in gravitational potential, but it also has some kinetic energy, which is the horizontal component of the ball when it was hit.
    For C, the ball again has almost all potential energy, due to the compression of the ball and the movement from the bat. This is also when the ball gets all the energy from the player transferred to it, and this energy will take it to its highest point.

    At first I was lead to believe that it was C, due to the fact that as it travels up it will lose energy to the air around it. But then I thought that when the ball is being hit, it still have kinetic energy due to that while in contact with the bat, the bat is moving forward. And people swing those bats pretty fast.
    The motion of a bat is upward though, so it had a vertical component of velocity along with horizontal. The velocity at the top is all horizontal, so the vertical component of velocity has been eliminated and thus the ball is moving faster at the bottom; it has more kinetic energy there.

    So it can be either B or C in my opinion, depending on how you want to interpret the velocity of the ball while it is in contact with the bat, or the energy dispersed as it is climbing to the top of its path.

    Did anybody else have any other factors that should be taken into consideration that I missed?
  9. Oct 12, 2011 #8
    looks good to me. Would it be fair to say that when the ball is in contact with the bat there is a portion of the ball that is static while it's undergoing an elastic collision?
  10. Oct 12, 2011 #9


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    Lots of weird discussion here.
    I believe the question is as simple as:

    It has the greatest Potential energy when it is at its highest.

    The pitchers hand, the swinging bat and the fielders mitt are ALL at approximately the same height - so if any one of them was correct, they would all be correct [there's a clue]

    At the top of the flight is where potential energy is greatest.

    A baseball is not a very elastic ball - try dropping one on to a basketball court and see how far it bounces - so there will be very little elastic potential energy "stored" in the ball. There may be some stored in the flexed bat, but we wanted the energy of the ball, not the bat.
    A "pop fly" sounds like one of those balls that goes [almost] straight up from the top edge of the bat. It is also a baseball term, so I don't really know - just as you may not know what "he put down a sharp chance at silly-mid-on" means.
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