  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.
The military combined with engineers and industrialists and by early 1916 a prototype was adopted as the design of future tanks. Britain used tanks in combat for the first time in the Battle of Flers-Courcelette on 15 September 1916.