Average and Marginal Product

In the context of a total production function curve, what does the slope of a ray from the origin to a point on the curve represent?

If the total product of labor is $L_1A$ when $OL_1$ units of labor are employed, how is the average product of labor calculated?

How is the marginal physical product of labour expressed when labour increases by $\Delta L$ units and output changes by $\Delta Q$?

What graphical element of the total production curve indicates the marginal product of labor at a specific employment level?

How does the average product of labor change as the ray from the origin to the total product curve moves from point B to point C (assuming C is further along the curve)?

Average Product of Labour (APL)

Marginal Physical Product of Labour (MPPL)

Average Product (Graphical)

Marginal Product (Graphical)

Average product of labor can be measured.
When OL₁ units of labor are employed, total product equals L₁A.
The average product of labor equals L₁A/OL₁, which is the slope of ray OA.
When OL₂ units of labor are employed, total product (TP) is L₂B.
The average product equals L₂B/OL₂ or the slope of ray OB.
With labor equal to OL₃, the average product is measured by the slope of ray OC.
As more units of a factor are employed, the average product rises, then falls.
The average product curve of a variable factor rises and then declines, forming an inverted U-shape

Marginal Product

Marginal product of a factor is the addition to total production from employing an extra unit of that factor.
Two workers produce 170 quintals of wheat per year.
Three workers produce 270 quintals; the third worker added 100 quintals.
100 quintals represents the marginal product of the third worker.
Marginal product of labor increases initially, then diminishes.
The marginal product of the 8th unit of labor is zero, and becomes negative beyond that.
Mathematically, if labor increases by ΔL, and total output increases by ΔQ, the marginal physical product of labor is given by ΔQ/ΔL.
MP = ΔQ/ΔL
The marginal physical product curve of a variable factor can be derived from the total physical product curve of labor.
At any given level of labor employment, the marginal product of labor is the slope of the total product curve at that level.

Explanation of average and marginal product of labor. Includes how to measure average product using slopes of rays and the concept of marginal product as the addition to total production from employing an extra unit of a factor.