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Acceleration Due to Gravity Question

  1. Mar 5, 2008 #1
    Quick question...

    If you were to throw an object (such as a baseball) straight downward, would the acceleration of the object still be -9.8m/s/s?
     
  2. jcsd
  3. Mar 5, 2008 #2

    rcgldr

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    Ignoring aerodynamic drag, and assuming that the distance from earth isn't signicantly large, then velcocity doesn't affect the gravitational acceleration.

    For a similar example, imagine a rocket in space. It's acceleration is a function of thrust versus mass of the rocket and is also independent of the rockets velocity.
     
  4. Mar 5, 2008 #3
    Jeff is right, from what I can tell. The initial velocity plays no part in the acceleration of an object in free fall.

    Quick question there, Jeff. When you say thrust, are you basically counting it as a 'force' that acts against the mass? I'm relatively new to physics so I'm just trying to understand what I can.
     
  5. Mar 5, 2008 #4
    Before the object leaves your hand, its acceleration may be higher than gravitational acceleration. But after it comes off your hand, the acceleration is exactly g (not taken air drag into account) because gravity is only force that exerts on.
     
  6. Mar 5, 2008 #5
    think about it if you throw it straight down its has an initial velocity only. In ideal physics your acceleration due to gravity should be only 9.8m/s on free falling objects.
     
  7. Mar 5, 2008 #6

    rcgldr

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    Yes, thrust is simply a force, and doesn't take into account the speed at which the force is applied. Force times speed equals power, for example, force in lbs, times speed in mph, divided by 375 (conversion factor) calculates horsepower.
     
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