SATHEE: Work Energy and Power - Result Question 35

Work Energy and Power - Result Question 35

38. The heart of man pumps 5 litres of blood through the arteries per minute at a pressure of $150 m m$ of mercury. If the density of mercury be $13.6 \times 10^{3} k g / m^{3}$ and $g = 10 m / s^{2}$ then the power of heart in watt is :

(a) 2.35

(b) 3.0

(d) 1.70

[2015 RS]

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Answer:

Correct Answer: 38. (d)

Solution:

(d) Work done by the heart, $W = P Δ V$

where, pressure $P = ρ g h$

and $h = 150 m m - 0.15 m$

$\begin{aligned} g = 10 m / s e c^{2} \\ ρ = 13.6 \times 10^{3} k g / m^{3} \end{aligned}$

So, Power $= \frac{W}{t} = \frac{P \cdot Δ V}{t}$

Power $= \frac{ρ g h \times 5 \times 10^{- 3}}{60}$

$\Rightarrow \frac{13.6 \times 10^{3} \times 10 \times 0.15 \times 5 \times 10^{- 3}}{60}$

$\Rightarrow 1.7$ watt

Power $\vec{F} \cdot \vec{V} = P A \vec{V} = ρ g h A V$

$[∵ P = \frac{F}{A} .$ and $. P = ρ g h]$

$∴ P = 13.6 \times 10^{3} \times 10 \times 150 \times 10^{- 3} \times 0.5 \times 10^{- 3} / 60$

$= \frac{102}{60} = 1.70$ watt

Work Energy and Power - Result Question 35

38. The heart of man pumps 5 litres of blood through the arteries per minute at a pressure of $150 m m$ of mercury. If the density of mercury be $13.6 \times 10^{3} k g / m^{3}$ and $g = 10 m / s^{2}$ then the power of heart in watt is :

Answer:

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Work Energy and Power - Result Question 35

38. The heart of man pumps 5 litres of blood through the arteries per minute at a pressure of 150mm of mercury. If the density of mercury be 13.6×103kg/m3 and g=10m/s2 then the power of heart in watt is :

Answer:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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38. The heart of man pumps 5 litres of blood through the arteries per minute at a pressure of $150 m m$ of mercury. If the density of mercury be $13.6 \times 10^{3} k g / m^{3}$ and $g = 10 m / s^{2}$ then the power of heart in watt is :