Ahockey puck is set in motion across a frozen pond. if ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

Mmm tricky.
Constant velocity means there's no net force acting on the puck!

So if there's no friction or air drag force to slow it down, you don't need any force to keep that puck moving.

Once it's in motion, it stays in motion.
(Mmm isn't that a Law of Newton?)
:D

Sound energy is produced when an object vibrates. examples are 1- a balloon popping2-a whistle3- a waterfall