Robins used the ballistic pendulum to measure projectile velocity in two ways.

As the suspended body constituted a ballistic pendulum, this measured the relative momentum of the rounds to some extent.

Simple ballistic pendulum problems obey the conservation of kinetic energy only when the block swings to its largest angle.

But then they failed to reproduce the effect in a pendulum system, using a rocket-powered ballistic pendulum.

In practice, it is often simpler to derive the gun's energy directly with a reading from a ballistic pendulum or ballistic chronograph.

A ballistic pendulum is a device for measuring a bullet's momentum, from which it is possible to calculate the velocity and kinetic energy.

Ballistic pendulums have been largely rendered obsolete by modern chronographs, which allow direct measurement of the projectile velocity.

The ballistic pendulum is still found in physics classrooms today, because of its simplicity and usefulness in demonstrating properties of momentum and energy.

Although the ballistic pendulum is considered obsolete, it remained in use for a significant length of time and led to great advances in the science of ballistics.

The force measuring setups have ranged from various load cell devices to ballistic pendulums to multiple torsion arm pendulums, in which movement is actually observed.

Around 1800, the ballistic pendulum was used to measure the momentum of the projectile fired by a gun; dividing the momentum by the projectile mass gives the velocity.

In addition its primary uses of measuring the velocity of a projectile or the recoil of a gun, the ballistic pendulum can be used to measure any transfer of momentum.

Unlike other methods of measuring the speed of a bullet, the basic calculations for a ballistic pendulum do not require any measurement of time, but rely only on measures of mass and distance.

In particular he carried out an extensive series of experiments in gunnery, embodying his results in his famous treatise on New Principles in Gunnery (1742), which contains a description of his ballistic pendulum (see chronograph).

For example, a ballistic pendulum was used by physicist C. V. Boys to measure the elasticity of golf balls, and by physicist Peter Guthrie Tait to measure the effect that spin had on the distance a golf ball traveled.

The ballistic pendulum was invented in 1742 by English mathematician Benjamin Robins (1707-1751), and published in his book New Principles of Gunnery, which revolutionized the science of ballistics, as it provided the first way to accurately measure the velocity of a bullet.