A healthy adult of height 1.7 m has an average blood pressure (BP) of 100 mm of Hg. The heart is typically at a height of 1.3 m from the foot. Take, the density of blood to be 103 kg/m3 and note that 100 mm of Hg is equivalent to 13.3 kPa (kilo pascals). The ratio of BP in the foot region to that in the head region is close to

Question

A healthy adult of height 1.7 m has an average blood pressure (BP) of 100 mm of Hg. The heart is typically at a height of 1.3 m from the foot. Take, the density of blood to be 103 kg/m3 and note that 100 mm of Hg is equivalent to 13.3 kPa (kilo pascals). The ratio of BP in the foot region to that in the head region is close to (A) one (B) two (C) three (D) four

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/bdc9fe7f4d51680847a82a8cca12073a-.png" /> Pressure at head level = p textheart - ρ gh = 13.3-103 × 10 × 0.4 = 9.3 kPa Pressure at foot level = P textheart+ ρ gh = 13.3+ 103 × 10 × 1.3 = 26.3 kPa So, ratio = (26.3/9.3) ≈ 2.9 or 3

one

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Pressure at head level =pheart​−ρgh =13.3−103×10×0.4 =9.3kPa Pressure at foot level =Pheart​+ρgh =13.3+103×10×1.3 =26.3kPa So, ratio =9.326.3​≈2.9 or 3

Pressure at head level $= p_{heart} - ρ g h$

$= 13.3 - 1 0^{3} \times 10 \times 0.4$

$= 9.3 k P a$

Pressure at foot level $= P_{heart} + ρ g h$

$= 13.3 + 1 0^{3} \times 10 \times 1.3$

$= 26.3 k P a$

So, ratio $= \frac{26.3}{9.3} \approx 2.9$ or $3$