What is Momentum?

Momentum is how much motion something has, and it depends on how heavy it is and how fast it’s moving. If something is big and moving fast, it has a lot of momentum. For example, a moving truck has way more momentum than a bicycle going the same speed, because the truck is much heavier. The more momentum something has, the harder it is to stop. So, if something is light and slow, it’s easy to stop. But if it’s heavy and fast, you’ll need a lot of force to stop it. In short, momentum is like a mix of weight and speed that tells us how hard it is to stop something once it’s moving.