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.
Social Security retirement age. To help improve Social Security's finances, Congress decided that the retirement age should be raised to 67. This is phased in gradually, starting with retirees who were born in 1955. For retirees born in 1954 or earlier, full or normal retirement age is 66 years of age. After that, two months are added to the full retirement age for every year until 1960, when the full retirement age reaches 67. With that in mind, here's a chart that can help you determine your full retirement age: