What is the difference between speed, velocity, and acceleration?
Three Racing Siblings
What is the difference between speed, velocity, and acceleration?
There are three words that physics teachers love and students mix up: speed, velocity, and acceleration. They sound like triplets. They are not. They are more like three siblings with very different personalities, and once you've met each one properly, you'll never confuse them again.
Start with speed, the simplest of the three. Speed answers exactly one question: how fast? It's a number with a unit stuck to it, like "60 kilometers per hour" or "two steps per second." That's all speed cares about. It never asks where you're going. A car doing 60 north and a car doing 60 south have the exact same speed.
