CHAPTER 1 SLOW DOWN Nick straps on his helmet and steps onto his skateboard He pushes off with his foot At first he rolls along quickly But soon he starts to slow down Wheels help people move faster than they could by walking
The skateboard’s wheels are attached to axles The skateboard slows down partly because of the friction between the wheels and the axles Friction happens when two objects rub against each other Once again Nick pushes against the street with his foot His skateboard starts to roll faster He is moving quickly when he sees his friend Anna He wants to stop and talk to her Nick puts down his foot He drags it against the street
The friction between the shoe and the ground helps the rider slow down
