Aweaver+Ballistic+Pendulum+Lab

A ballistic pendulum is a device used to measure an object's momentum. It is usually used for bullets. It is now generally obselete due to chronographs which allow direct measurment of projectile velocity. However, it was useful for a long while before that. The ballistic pendulum was invented in 1742 by Benjamin Robins. A gun was attached to the pendulum, and a bullet was fired. The mass of the block as well as the mass of the bullet being fired needed to be noted. Also, the height of the pendulum's swing had to be measured. Approximate muzzle velocity could then be determined through conservation of momentum. Conservation of energy could not be used because during the collision, an unknown amount of energy is lost through internal forces. Principles involved include kinetic energy, potential energy, conservation of mometum, and elastic/inelastic collisions.



The approximate velocity of a bullet could be determined through this process. If the masses as well as the height were known, conservation of momentum could be used to solve for the bullet's velocity.



In physics classes, more modern ballistic pendulums are usually used. The object is fired directly into the pendulum, providing more accurate estimations.

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