For 10 points, name this quantity that generally equals force divided by area.
The time average of the Poynting vector divided by the speed of light equals one form of this quantity. A solar sail, which is a form of spacecraft propulsion, is based on the radiation type of it. Another form of this quantity that is based on a property of electrons supports a white dwarf from collapsing. The transmission of this quantity in a fluid is the subject of Pascal's principle. The gauge form of this quantity equals the difference between the absolute and atmospheric types of it. For 10 points, name this quantity that generally equals force divided by area.
The time average of the Poynting vector divided by the speed of light equals one form of this quantity.
pressure [accept specific types]