Dunkirk: Where History Happened. We visit 10 places connected with the remarkable evacuation of the British Expeditionary Force from northern France in 1940. This feature was first published in the April 2010 edition of BBC History Magazine. Tuesday 25th May 2010.
The seepage velocity is less than the actual flow rate of the liquid or gas in the pores because the fluid moves only through the portion of the cross-sectional area S that is occupied by the pores.
Instantaneous velocity is the velocity of an object at a single point in time and space as calculated by the slope of the tangent line. Differentiate instantaneous velocity from other ways of determining velocity. When velocity is constantly changing, we can estimate our velocity by looking at instantaneous velocity.