7.3
Curvas de Custo Fixo Total, Variável Total e Custo Total
No curto prazo, uma empresa incorre em várias despesas fixas, como pagamentos de aluguel, prêmios de seguro e depreciação de máquinas. Coletivamente,…
Considere uma pequena empresa fazendo mesas. No curto prazo, incorre em custos fixos, incluindo aluguel de fábrica e manutenção de máquinas. A soma desses custos é chamada de custo fixo total ou TFC.
Graficamente, o TFC é uma linha horizontal paralela ao eixo x, pois permanece constante independentemente da saída.
Os custos variáveis incluem pagamentos de madeira e trabalho assalariado diário. A soma desses custos é o custo variável total ou TVC.
Na ausência de produção, o TVC é zero. À medida que a fabricação começa, o TVC aumenta porque os custos de madeira e mão de obra são incorridos. Devido ao crescente produto marginal do trabalho que existe na faixa inicial de produção, o TVC aumenta a uma taxa decrescente. No entanto, mais tarde, o TVC aumenta a uma taxa crescente devido ao eventual início da diminuição do produto marginal do trabalho. Nessa faixa de produção, os trabalhadores podem ficar ociosos, aguardando acesso a máquinas limitadas, resultando em menor produtividade.
O custo total ou TC é a soma de TFC e TVC. TC é semelhante ao TVC, e estes são paralelos. No entanto, o TC começa no ponto de custo fixo total, uma vez que esses são custos incorridos independentemente da produção.
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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.