I'm not sure that the upper limits of kinetic energy for slinging have been thoroughly explored. If I'm incorrect, please link me to the right discussion.

I've seen a 2.244 kg stone thrown at 17 m/s somewhere on here. Assuming spherical cows thrown at 45° in a vacuum (sorry), velocity = √(distance·9.8/sin(2·angle))

That yields:

• 38.1 kg·m/s
• 324.3 Joules
• 0.077 Calories

I don't think that there is an optimal size stone for achieving high energy, because it just depends on how big a stone the slinger can heft. As an example, a 100 kg projectile could be thrown one meter:

• 313 kg·m/s
• 490 Joules
• 0.117 Calories

Another example is the world record hammer throw of 23.56 meters with a 7.26 kilogram (16 pound) hammer. Using the same back-of-the-napkin math, this yields:

• 211.7 kg·m/s
• 3085.7 Joules
• 0.737 Calories

My calculations:
velocity based on distance.xlsx

What is the maximum energy that you have been able to produce with a sling?

I made an error on the the 1 meter 100 kilogram throw 😳

	kg·m/s	Joules	Calories
Error	4425.0	97903.1	23.4
Corrected	313.0	490.0	0.117

I corrected it in the original post.

@joe_meadmaker, I made more corrections this time to the estimations for the watermelon and 3 kg stone.