A jég megállítja a golyókat, és azok pörögni kezdenek? Szerintetek hamis vagy valódi?Az első videójuk.
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A jég megállítja a golyókat, és azok pörögni kezdenek? Szerintetek hamis vagy valódi?Az első videójuk.
A bullet fired from a gun will leave the barrel with a certain linear momentum and rotational momentum (caused by the rifling of the handgun barrel). The impact of the bullet with the ice is a semi-elastic collision (due to the fact that some energy is lost due to heat, displacement of the ice etc.) We allow for the fact that the ice will absorb some of the bullets linear momentum by the deformation of the ice resulting in a groove such as
_______ _______
/ /
\ /
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Not the exact angle or picture but work with me. After a certain point the ice will no longer deform and the ice will exert a force normal to the surface the bullet contacts, which is the left bottom angled face. Now the bullet is sent back in its former trajectory but with less linear momentum (energy lost in semi-elastic collision) so it returns in the line it was fired but doesn’t return the same distance.
Now to cause a change in angular momentum a force has to act perpendicular to the axis of rotation. The only force that could do this would be the frictional force of the ice. Considering that the frictional force of ice is small and that the impact hole in the ice is not snug around the bullet it is plausible that the rotational momentum was not fully absorbed in the time that it took for the bullet to ricochet. Reply