Editor's Note: The Hyperloop is a totally imaginary transportation device that has captivated entrepreneur Elon Musk, who keeps talking about it. First imagined at least 100 years ago, it would ...

Velocity-time graphs show how the velocity (or speed) of a moving object changes with time. These graphs also show if the object is moving at a constant speed or accelerating, decelerating, or still.

You're sitting in physics class, working on a traditional problem involving forces and acceleration, when you start to wonder where these terms even came from. Were they just dreamed up to bring ...

According to Newton's third law of motion, whenever two objects interact, they exert equal and opposite forces on each other. This is often worded as 'every action has an equal and opposite reaction'.