  The electron and the proton have a negative electrostatic charge and a positive electrostatic charge respectively. Each charge-and the force associated with that unit of charge-is constant-and equal.(The electron and proton have equal, but oppositely polarized, electrostatic charges.) But there is more. The electron and the proton have a negative electrostatic charge and a positive electrostatic charge respectively. Each charge-and the force associated with that unit of charge-is constant-and equal.
The start of life for the tank did not bode well. The first model came off the factory floor on September 8th 1915. On September 10th, its track came off. The same happened on September 19th when government officials were watching.
This arrangement was a forerunner of the modern submarine ballast tank. First use in war. The submarine was first used as an offensive weapon in naval warfare during the American Revolution (1775â83). The Turtle, a one-man craft invented by David Bushnell, a student at Yale, was built of wood in the shape of a walnut standing on end (see photograph).