No speed always single but if there will be a lot of speeds then it will be plural.
The plural form of the noun light is lights.The plural possessive form is lights'.
The plural form of energy is energies.
the plural form of friction is friction
physics is already in plural form.
The possessive form for the plural noun highways is highways'.
The plural form for the noun family is families; the plural possessive form is families'.Example: All of the families' efforts succeeded in getting the speed limit reduced.
No speed always single but if there will be a lot of speeds then it will be plural.
Bridges is the plural form of bridge.
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.
There is no plural form for the word, countries. This word itself is a plural.
"Groceries" is the plural form of "grocery."
The plural form of "meter" is "meters."
The plural form for the noun sergeant is sergeants; the plural possessive form is sergeants'.
It has no plural form.
The plural form of rung is rungs.
The plural form of mouth is mouths. The plural form of month is months. The Mounth is a range of hills in Scotland and does not have a plural form.