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.

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 ...

Light has fascinated scientists for centuries. Galileo Galilei was the first to consider measuring its speed. In 1676, astronomer Ole Roemer made observations of the eclipses of Jupiter's moons to ...