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Gravity and Projectile motion

  1. Aug 19, 2012 #1
    Why does a bullet fired horizontal and bullet dropped vertically downward, land at the same time? Shouldn't the object thrown downward fall sooner as it has a shorter distance to cover even though gravity pulls both of the down at the same rate?

    Does it have to do anything with the fact that the bullet which is fired has greater thrust?

    Would the same apply if the bullet was fired in both cases? i.e. both the bullets shot from a gun at the same velocity and speed, one vertically downward and the other horizontally.

    Also if a bullet shot from a gun travels in a parabolic path wouldn't that make it very hard to aim straight?

  2. jcsd
  3. Aug 19, 2012 #2


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    Neglecting air resistance (which does make a slight difference, but it's way beyond the scope of discussion) you can look at horizontal and vertical motions as completely separate. Both bullets have the same vertical distance to cover, and so take the same amount of time to cover that distance. Obviously, if you fire a gun straight down, rather than just drop the bullet, this bullet would get to ground much faster. Regardless, however, a bullet that has left the muzzle no longer experiences any thrust, and is in free projectile motion. And yes, it's something you have to take into account if you are aiming from long distance, and yes, it does make it quite a bit harder to hit your target.
  4. Aug 20, 2012 #3
    Thank you
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