One way to categorize waves is to say that there are longitudinal and transverse waves. In a transverse wave, particles of the medium are displaced in a direction perpendicular to the direction of energy transport. In a longitudinal wave, particles of the medium are displaced in a direction parallel to energy transport.
Seven plans allowed normal retirement within these ages. Six of them required at least 30 years of service for normal retirement. Only two of the plans continue to allow normal retirement within these ages. Both now require a minimum age of 57 and at least 30 years of service. For most plans the minimum age requirement increased to the range of age 60 to age 62. Age 60.
Eligibility is determined by your age and number of years of creditable service. In some cases, you must have reached the Minimum Retirement Age (MRA) to receive retirement benefits. Use the following chart to figure your Minimum Retirement Age.