Force
Assuming the gun and shooter are at rest, the force on the bullet is equal to that on the gun-shooter. This is due to Newton's third law of motion (For every action, there is an equal and opposite reaction). Consider a system where the gun and shooter have a combined mass M and the bullet has a mass m. When the gun is fired, the two systems move away from one another with new velocities V and v respectively. But the law of conservation of momentum states that the magnitudes of their momenta must be equal:
Since force equals the rate of change in momentum and the initial momenta are zero, the force on the bullet must therefore be the same as the force on the gun/shooter.
Hollywood depictions of firearm victims being thrown through plate-glass windows are inaccurate. Were this to be the case, the shooter would also be thrown backwards with equal force. Gunshot victims frequently fall or collapse when shot; this is less a result of the momentum of the bullet pushing them over, but is primarily caused by physical damage or psychological effects, perhaps combined with being off-balance. This is not the case if the victim is hit by heavier projectiles such as 20 mm cannon shell, where the momentum effects can be enormous; this is why very few such weapons can be fired without being mounted on a weapons platform or involve a recoilless system (e.g. a recoilless rifle).
Read more about this topic: Physics Of Firearms
Famous quotes containing the word force:
“Nations do not think, they only feel. They get their feelings at second hand through their temperaments, not their brains. A nation can be brought—by force of circumstances, not argument—to reconcile itself to any kind of government or religion that can be devised; in time it will fit itself to the required conditions; later it will prefer them and will fiercely fight for them.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“Science is unflinchingly deterministic, and it has begun to force its determinism into morals. On some shining tomorrow a psychoanalyst may be put into the box to prove that perjury is simply a compulsion neurosis, like beating time with the foot at a concert or counting the lampposts along the highway.”
—H.L. (Henry Lewis)
“In the new science of the twenty-first century, not physical force but spiritual force will lead the way. Mental and spiritual gifts will be more in demand than gifts of a physical nature. Extrasensory perception will take precedence over sensory perception. And in this sphere woman will again predominate.”
—Elizabeth Gould Davis (b. 1910)