1 The shape of the total product curve is determined by the marginal product of the variable factor, in this case labor. 2  As we increase the amount of labor, with a fixed factor, initially the marginal productivity of the variable factor (labor) goes up, as it gets better synchronized with the fixed factors. Upto this point (B) the total product increases at an increasing rate. 2  When the marginal productivity reaches its maximum, the total product reaches an inflexion point, and from that point on it increases but at a decreasing rate (B to C.).
Selection for commander -- the O-4 officer pay grade equivalent to a major in the Army, Air Force or Marine Corps -- requires that the candidate for promotion must have served three years as a lieutenant to meet the required time-in-grade.A lieutenant must also have between nine and 11 years of military service.ommander. Reaching the rank of commander, O-5, from the rank of lieutenant commander requires an officer to have served a total of three years as a lieutenant commander to meet the time-in-grade requirement. The officer must also have between 15 and 17 years of total military service.
DOPMA guidelines suggest all fully qualified officers should be promoted to first lieutenant. A second lieutenant (grade O-1) is usually promoted to first lieutenant (grade O-2) after 18 months in the Army or 24 months in the Air Force and Marine Corps.The difference between the two ranks is slight, primarily being experienced and having higher pay.t is just above the rank of second lieutenant and just below the rank of captain. It is equivalent to the rank of lieutenant (junior grade) in the other uniformed services. Promotion to first lieutenant is governed by Department of Defense policies derived from the Defense Officer Personnel Management Act of 1980.