The other variable depends on the first, so it gets the name dependent . In a scientific experiment, the experimenter chooses values for the independent variable, runs the experiment, and then measures the dependent variable. The independent variable is traditionally plotted on the horizontal axis. Notice that this energy of motion is proportional to the square of the speed. One of the undefined qualities of physics, mass is the measure of inertia The position of an object is its distance from zero.
Power is the rate of working.
Speed is simply the rate of position change, but for analysis and problem solving speed has several faces. The speed at an instant is can be approximated with an average speed measured over a short time interval. Initial speed is the speed of an object at the beginning of a measurement, an intial condition. The average speed is the ratio of distance covered to the time it takes, or the average of the final and intial speeds. The change in speed is the difference between final and inital speeds.