The two thigh bones, each of cross-sectional area 10 cm 2 support the upper part of a human body of mass 40 kg. Estimate the average pressure sustained by the bones. Take g=10 m / s 2

Question

The two thigh bones, each of cross-sectional area 10 cm 2 support the upper part of a human body of mass 40 kg. Estimate the average pressure sustained by the bones. Take g=10 m / s 2 (A) 2 × 105 N / m 2 (B) 5 × 104 N / m 2 (C) 2 × 107 N / m 2 (D) 3 × 106 N / m 2

Tardigrade Admin · Accepted Answer

Total cross-sectional area of the thigh bones A=2(10 × 10-4)=2 × 10-3 m 2 Force acting on the bones =m g=40 × 10=400 N ∴ P av =(F/A)=(400/2 × 10-3)=2 × 105 N / m 2

Q. The two thigh bones, each of cross-sectional area $10 c m^{2}$ support the upper part of a human body of mass $40 k g$ . Estimate the average pressure sustained by the bones. Take $g = 10 m / s^{2}$

$2 \times 1 0^{5} N / m^{2}$

$5 \times 1 0^{4} N / m^{2}$

$2 \times 1 0^{7} N / m^{2}$

$3 \times 1 0^{6} N / m^{2}$

Total cross-sectional area of the thigh bones
$A = 2 (10 \times 1 0^{- 4}) = 2 \times 1 0^{- 3} m^{2}$
Force acting on the bones $= m g = 40 \times 10 = 400 N$
$∴ P_{a v} = \frac{F}{A} = \frac{400}{2 \times 1 0 ^{- 3}} = 2 \times 1 0^{5} N / m^{2}$

Q. The two thigh bones, each of cross-sectional area 10cm2 support the upper part of a human body of mass 40kg. Estimate the average pressure sustained by the bones. Take g=10m/s2

2×105N/m2

5×104N/m2

2×107N/m2

3×106N/m2