Today we learnt about friction, rotational motion and momentum.
When you are roller skating you are moving. When you want to stop moving you use the toe-stoppers. The toe-stoppers are made out of rubber and you drag them on the ground to create friction. This will make you stop.
Roller skates have wheels. The wheels spin in a circle which makes the roller skates move. This is called rotational motion. Momentum is equal to mass times speed. This is how heavy an object is times how fast it's going. If Mum and I were both skating at the same speed, Mum would have the most momentum because she is heavier.