The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum, and also to a slight degree on the amplitude, the width of the pendulum's swing.he period of swing of a simple gravity pendulum depends on its length, the local strength of gravity, and to a small extent on the maximum angle that the pendulum swings away from vertical, Î¸0, called the amplitude.
Compulsory elementary schooling was formally introduced in Sweden in 1842. A process of reform, destined to take many years, began in the 1940's with the aim of expanding compulsory schooling.
Conscription in Britain, 1939   It was introduced in April, 1939 and was the first time Britain had ever introduced compulsory military service in peace time.