News & Analysis
/
Article

How far will the sling bullet go?

APR 25, 2025
Equations suitable for teaching can predict how well a sling will perform
Hannah Daniel Headshot.jpg
Media Relations Specialist
How far will the sling bullet go? internal name

How far will the sling bullet go? lead image

Before rockets, guns, and cannons, humans had slings. Along with arrows and catapults, these ancient weapons allowed launching objects much farther — and harder — than a human was capable of unequipped.

A sling is made of two cords, a retention cord and a release cord, with a pouch in the middle to hold the thrown object, called a bullet. As a physicist and historian enthusiast, Mark Denny derived multiple equations to predict the launch speed of the launched bullet based on the parameters of the sling.

“The sling is a simple machine, but analyzing how a slinger launches a sling bullet is very complicated because of the movements made by the slinger during the launch phase,” said Denny.

In his first set of equations, Denny describes a thrower launching the sling bullet in a pirouette style similar to an Olympic hammer throw.

He also derives equations to determine the bullet spin and timing error in terms of target range.

In another set of equations, Denny considers the motion of a side-arm sling, which is performed with a single arm where the sling is rotated overhead. This equation determines the motion of the sling based on the average power transferred to the bullet by the slinger.

Together, these equations can help to characterize the ability of most sling designs.

“This research will be useful to, for example, archaeologists who dig up an ancient sling and wonder how well it performed,” Denny said.

It can also be used as a teaching model for students investigating the internal ballistics of the weapon.

Source: “Internal ballistics of the sling,” by Mark Denny, American Journal of Physics (2025). The article can be accessed at https://doi.org/10.1119/5.0226263 .

More Science
/
Article
Data from a polar vortex splitting during 2002’s Southern Hemisphere sudden warming event helps expand models to accommodate spherical cap geometry found in stratospheric polar vortices.
/
Article
Tabletop device quickly and cheaply creates high-quality graphene flakes for research use.
AAS
/
Article
Brr! A newly confirmed exoplanet orbiting a white dwarf has a temperature of just 186K, making it the coldest exoplanet whose light has been directly detected.
/
Article
Material advances overcome major hurdles to photocatalytic energy production and more than double energy production efficiency across a range of pH levels.