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Q9.7: NCERT Physics - Part 2 MECHANICAL PROPERTIES OF FLUIDS 9.7 Solution: A vertical off-shore structure is built to withstand a maximum…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often compute hydrostatic pressure $P=\rho gh$ and compare it directly to a material’s stress limit, forgetting to add the ambient atmospheric pressure (~$1\times10^5$ Pa). Always use the absolute pressure $P_{\text{abs}}=P_{\text{atm}}+\rho gh$ before checking against the allowable stress, even if the extra term seems small.

A vertical off-shore structure is built to withstand a maximum stress of 10910^9 Pa. Is the structure suitable for putting up on top of an oil well in the ocean? Take the depth of the ocean to be roughly 3 km, and ignore ocean currents.

Step-by-Step Verified Solution

**Answer:** Yes, the structure is suitable. **Step-by-Step Explanation:** Depth h=3h = 3 km =3000= 3000 m, density of seawater ρ=1030\rho = 1030 kg/m_. Pressure at that depth:
P=ρgh=1030×9.8×3000=3.03×107 PaP = \rho g h = 1030 \times 9.8 \times 3000 = 3.03 \times 10^7 \text{ Pa}
Since 3.03×1073.03 \times 10^7 Pa <109< 10^9 Pa, the structure can withstand the pressure.

All Questions in this Chapter

Q9.1 Q9.2 Q9.3 Q9.4 Q9.5 Q9.6 Q9.7 Q9.8 Q9.9 Q9.10 Q9.11 Q9.12 Q9.13 Q9.14 Q9.15 Q9.16 Q9.17 Q9.18 Q9.19 Q9.20

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