A block of wood (dimensions: 40~cm\times 20~cm\times 10~cm) is kept on a tabletop in three different positions : (a) with its side of dimensions 20\text{ cm} \times 10\text{ cm}; (b) with its side of dimensions 10~cm\times 40~cm; and (c) with its side of dimensions 40~cm\times 20~cm. The pressure exerted by the wooden block on the tabletop in these positions is represented by P_{A}, P_{B} and P_{C}, respectively. The pressure follows the trend

  1. A. P_{A}>P_{B}>P_{C} ✓
  2. B. P_{A} \lt P_{B} \lt P_{C}
  3. C. P_{A}=P_{B}=P_{C}
  4. D. P_{A} \lt P_{B} = P_{C}

Correct Answer: A. P_{A}>P_{B}>P_{C}

Explanation

Pressure is inversely proportional to the area of contact (P = F/A). The contact areas are A_{A} = 200\text{ cm}^{2}, A_{B} = 400\text{ cm}^{2}, and A_{C} = 800\text{ cm}^{2}. Since A_{A} < A_{B} < A_{C}, the pressure trend is P_{A} > P_{B} > P_{C}.

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