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Why must rockets and bullets spin

  1. Apr 1, 2004 #1
    why must rockets and bullets spin when they are in motion in order to move in the intended motion?
    what does the spinning motion do?
    does it produce a force to matian the centre of gravity at the centre? and what if the bullet is a perfect sphere, does it still need to spin?
  2. jcsd
  3. Apr 1, 2004 #2
    It is not too uncommon for a modern rifle of high quality to shoot a five-shot group of less than 1 inch at 100 yds.

    Without spinning, the long pointed bullets that we use today would tumble in flight. Each shot would impact in a different county(slight exaggeration).

    If a spherical projectile is fired from a rifled bore with the proper "twist", one can expect to get a five-shot group at 100 yds of 2" or less with a rifle of decent quality. Rifles shooting round balls were capable of this kind of accuracy over 100 years ago.

    If the same type spherical ball is fired from a smooth bore rifle, the group sizes run from 1 to 3 FEET at 100 yds. Early rifles weren't much better than long bows in battle, and in many situations, weren't as good.

    Last edited by a moderator: Apr 1, 2004
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