The Catch Game Ever tried catching a ping-pong ball and a baseball thrown at the same speed? You've noticed, haven't you, that the baseball stings a bit more. Or think about the difference between a gently tossed baseball and a fast-pitch from a pro. It's the same ball, but those catches feel very different. Why is that? Welcome to the world of force and momentum.

Momentum is the combo of an object's mass and velocity, not speed. If you have a math-nerd side, it's simply: p = m × v.Just remember

• Momentum is a vector: It has direction! So a 1 kg apple falling straight down has a different momentum than a 1 kg apple flying sideways.
• Unit of Momentum: It's kgms⁻¹, which sounds like a trendy music group, but it's just kilograms multiplied by meters per second.
• Momentum changes: If mass or velocity changes, then the momentum changes too. That's why a baseball coming towards you at a faster speed or a heavier ball coming at the same speed seems harder to catch – they have more momentum!