7.3
合計固定曲線、合計変動曲線、および合計コスト曲線
短期的には、リース料、保険料、機械の減価償却費など、さまざまな固定費が発生します。これらを総称して、生産の総固定費(TFC)と呼びます。グラフィカルには、TFC は x 軸に平行な直線で表され、縦軸にコスト、横軸に出力量が表示されます。
変動費には、使用される材料や時給労働者の賃金など、出力レベルに…
テーブルを作る小さな会社を考えてみましょう。短期的には、工場のレンタル料や機械のメンテナンスなどの固定費が発生します。これらのコストの合計は、総固定費またはTFCと呼ばれます。
グラフィカルには、TFCは出力に関係なく一定であるため、x軸に平行な水平線です。
変動費には、木材の支払いと日雇い労働が含まれます。これらのコストの合計が、変動費の合計または TVC です。
プロダクションがない場合、TVCはゼロです。製造が始まると、木材や人件費が発生するため、TVCが増加します。初期の生産範囲に存在する労働の限界生産物の増加により、TVCは減少速度で上昇します。しかし、その後、労働の限界生産物が最終的に減少し始めるため、TVCは増加速度で上昇します。この出力範囲では、労働者はアイドル状態になり、限られた機械へのアクセスを待っている可能性があり、その結果、生産性が低下します。
総コストまたはTCは、TFCとTVCの合計です。TC は TVC に似ており、これらは並列です。ただし、TCは、出力に関係なく発生するコストであるため、合計固定コストポイントから開始されます。
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Q1: What is total fixed cost and why does it remain constant on a cost curve?
Total fixed cost (TFC) represents expenses a firm incurs regardless of output level, such as factory rent and machine maintenance. Graphically, TFC appears as a horizontal line parallel to the x-axis because these costs remain constant whether the firm produces zero units or maximum capacity. This unchanging nature distinguishes fixed costs from variable expenses.
Q2: How does total variable cost behave as production increases?
Total variable cost (TVC) starts at zero when no production occurs and increases as output rises. Initially, TVC increases at a diminishing rate due to increasing marginal product of labor. Later, TVC rises at an accelerating rate when diminishing marginal product of labor sets in, as workers become idle waiting for limited machinery access, reducing overall productivity.
Q3: What expenses are included in total variable cost for a manufacturing firm?
Total variable cost (TVC) includes all expenses that change with production levels, such as raw materials like wood and hourly wage labor payments. These costs directly correlate with output quantity—the more a firm produces, the higher its variable costs become, making them distinct from fixed expenses like rent.
Q4: How is total cost calculated and why is it parallel to the total variable cost curve?
Total cost (TC) equals the sum of total fixed cost (TFC) and total variable cost (TVC). The TC curve is parallel to the TVC curve because the vertical distance between them—the fixed cost—remains constant across all output levels. TC simply shifts the TVC curve upward by the amount of fixed costs incurred.
Q5: Why does the total cost curve start above the origin on a graph?
The total cost curve starts above the origin because it begins at the total fixed cost point. Even when production is zero, the firm still incurs fixed expenses like rent and machine maintenance. This starting point reflects costs the firm must pay regardless of whether any output is produced.
Q6: What causes the shape of the total variable cost curve to change from gentle to steep?
The TVC curve's shape reflects labor productivity changes. Initially, increasing marginal product of labor causes TVC to rise gently at a lower rate. As production expands, diminishing marginal product of labor emerges, causing TVC to rise steeply. Workers experience idle time waiting for limited machinery, reducing efficiency and increasing costs per unit produced.
Q7: How do fixed and variable costs differ in their relationship to production output?
Fixed costs remain constant regardless of output level, while variable costs change directly with production quantity. Fixed costs like rent and machine maintenance are unavoidable short-run expenses, whereas variable costs such as materials and labor scale with production volume. Understanding this distinction is essential for analyzing cost behavior and profitability.