How can you use a roller skate a sidewalk and watermto demonstrate how rollind friction works?

Answer 1

If you push a rollerskate down the sidewalk and don't keep pushing it, rolling friction will eventually cause it to stop on its own (assuming that the sidewalk is level and not on a hill)

Answer 2

As you roll across the sidewalk your blades are making a rolling friction. If you hit a water puddle it will slow your rolling friction down.