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A ballistic pendulum is a device used to measure the velocity of a projectile, typically a bullet. Here’s how it works:

  1. Setup: The ballistic pendulum consists of a heavy block or pendulum suspended by strings or a pivot, allowing it to swing in a restricted plane.
  2. Firing: A projectile, such as a bullet, is fired into the pendulum block. Upon impact, the bullet becomes embedded in the block, causing the pendulum to swing upward.
  3. Measurement: The maximum height reached by the pendulum after being struck by the bullet is measured. This height corresponds to the initial kinetic energy transferred from the bullet to the pendulum.
  4. Calculating Velocity: By measuring the angle of swing or the height attained by the pendulum and knowing the mass of the bullet and the pendulum block, the initial velocity of the bullet can be calculated using principles of conservation of momentum and energy.

The ballistic pendulum was historically used to measure bullet velocities before the advent of more modern methods like chronographs. It relies on the conversion of kinetic energy from the bullet into potential energy of the pendulum system, providing a practical means to determine projectile velocities in various applications, including firearms testing and ballistics research.

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