Is a signal that represents a continuous measure of a time-varying signal, in contrast to a digital signal, which measures a time-varying signal at discrete intervals.

Analog signal.

Explanation:

An analog signal can be say that  the signal which is continuous, for which the feature of time variation of the signal can be a representation of some other quantity of  time variation in signal.

This signal varies with respect to digital signals, which gives the values which are discrete at each point of sampling, it posses constant fluctuations.

Therefore, by the above it can be say that thew analog signal is a continuous representation of a time varying signal  as compare to digital signal, which can measure a signal of time varying at a discrete interval.

it is called kinetic energy