  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.
With the exception of the few interim Mark II and Mark III tanks, it was followed by the largely similar Mark IV, which first saw combat in June 1917. The Mark IV was used en masse (about 460 tanks) at the Battle of Cambrai in November 1917. The Mark V, with its much improved transmission, entered service in mid-1918.he Mark I was the world's first tank to enter combat. Born of the need to break the domination of trenches, barbed wire and machine guns over the battlefields of the Western Front, it was the first vehicle to be named tank, a name chosen as an expedient to maintain secrecy and to disguise its true purpose.