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 ...

Acceleration = change of velocity ÷ time taken. is shown by a straight rising line, A. Constant retardation (or deceleration) is shown by a straight falling line, C. Constant velocity is shown by a ...

gradient = \(\frac{change~in~y}{change~in~x} = \frac{change~in~speed}{change~in~time} = \) \( \frac{change~in~metres~per~second}{change~in~seconds}\) = metres per ...