### rate | velocity:

Conduction velocity
* depends on resistivity of the axoplasm and on the membrane capacitance.
* is slowest in the AV and sinoatrial nodes
  - the speed at which the compound nerve action potential traverses a nerve

Instantaneous velocity
* is the first derivative of displacement with respect to time
  - instantaneous speed plus the direction the object is headed
* refers to the velocity of an object at a specific point in time.

Orbital velocity
* depends only on the radius of an object's orbit.
* is the speed needed to stay in orbit.

River velocity
* determines quantity and size of rock fragments and sediment carried by the river.
* is generally greater on the outside of a bend, where the current often accelerates.

Seismic velocity
* Seismic velocities vary greatly with the type of rock or medium.
* can be a good proxy for the types of rocks at depth.

Vertical velocity
* Vertical velocities reach their maxima when the still water crossings occur.
* is the speed at which the air is rising or sinking
  - well correlated with temperature, resulting in a vertical heat flux

### rate | velocity:

Wind velocity
* Wind velocities increase as winter approaches
  - with altitude above the water
* accelerates body heat loss under conditions of both coldness and wetness.
* can have major effects on early plant growth and development.
* is considered a vector, as it represents both the wind's magnitude and direction
  - different at ground level than at higher altitudes, and can change quickly
  - highest at the shoreline, as is the frequency of flooding and the wave energy
  - illustrated as vector arrows, colored by speed
  - measured by means of an anemometer or radar
  - stronger during the winter months and weakest during late summer
  - the dominant environmental condition affecting spray drift

Wage rate
* Wage Rate measures the initial wage rate at placement and wage gains at designated followup periods.
* are an amount of income stipulated for a given unit of work or time
  - the result of labor demand and supply in labor markets
* determine total remuneration and measure women's contribution to total production.

### rates:

Event rate
* Event Rate is the proportion of patients in a group in whom an the event is observed.
* are rates.

Ratio
* are fractions that compare one part to another part
  - measures of individual performance and are calculated on a within-herd basis
  - ratios
  - real numbers
  - the quotients of the future and baseline periods
* describe the various relationships among accounts in the balance sheet and income statement.
* inherently give the relative relation of one variable to another.
* is computed by dividing dry ingredients by liquid.
* is the proportion between the times a banner is shown and the times users clicked on it
  - of wounded in action to combat deaths
  - security price divided by earnings per share
* just means the relation between two numbers.
* measure performance through comparisons of results.
* refers to how much the fuel-air mixture in the cylinder needs to compressed before ignition.
* word of broad meaning.

### ratio scales:

Physical measurement
* Most physical measurements are ratio scales.
* have to do with objective masses, forces, and energies.

### ratio:

Aspect ratio
* are ratios.
* comparison between the length and width of a wing.
* describes the ratio of the width to the height of the screen.
* has to do with the ration of the blade's legnth to the blade's width.
* is the ratio of the image width to the height
  - larger dimension of a rectangle to the smaller dimension
  - width to height
  - relationship between the width and height of a television picture
* is, for more complex shapes the wing span squared divided by the wing area.
* measure of how long and slender a wing is from tip to tip.
* plays an important role in phase change heat transfer mechanism.
* refers to the ratio of width to height of a television set.