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Calculate Distance, Time or Speed
Example: the villain with the parachute jumps out of the crashing plane, which is flying at 400 km/h. The hero without a parachute follows 5 seconds later. The plane has now flown 556 meters, so it should be difficult for the hero to catch the villain in the air.
Distance is the interal length between two points; it can be a straight line or one with curves. Time is harder to define; it indicates a sequence of events. Distance is one dimension of space; the other two dimensions are irrelevant here. Time is a dimension in its own right; distance and time are dimensions of four-dimensional space-time. Speed indicates how much the spatial dimension changes when the time dimension changes. Or more simply: how far something moves in what time. Speed is usually an average value. A change in speed is called acceleration; if it gets faster, acceleration in the opposite direction is called deceleration.
To put it mathematically, velocity or speed is the first derivative of distance with respect to time. Acceleration is the second derivative of distance with respect to time. The third derivative of distance with respect to time is called jerk, this is used less frequently.
Physics commonly uses SI units. Here is a calculator to convert units.
