How to use a sling?

[Havok.]

So, is the overhead motion more effective than circling the entire arm? Because it seems like it would be the opposite, as there would be more power in swinging the entire arm than just the sling. Or is it a matter of speed?

I think increasing the speed increase the power of it
q=mxv
since i dont know which are the better words to describe that formula i just translated literally
amount of movement=mass x speed

so therefore, increasing the speed would increase the power (amount of movement)

not sure if this is right though