What state of matter would spread apart and fill all the space available to them

work done by tension force on the twirled stone must be ZERO always

Explanation:

As we know that work done by a force on an object is given as

here we know that

= angle between force and displacement

now we know that tension in the string and displacement of the object is always perpendicular to each other when the rock is twirled in circular path.

so we can say for this motion of the stone

so work done by tension force on the twirled stone must be ZERO always