A steel rod has a radius R = 9.5 mm and length L = 81 cm . A force F = 6.2 × 104 N stretches it along its length. What is the stress in the rod?

Question

A steel rod has a radius R = 9.5 mm and length L = 81 cm . A force F = 6.2 × 104 N stretches it along its length. What is the stress in the rod? (A)  0.95 × 108 N/m2  (B)  1.1 × 108 N/m2  (C)  2.2 × 108 N/m2  (D)  3.2 × 108 N/m2

Tardigrade Admin · Accepted Answer

Stress = (F/A) = (6.2× 104/π r2) = (6.2× 104/3.1× (9.5)2 × (10-3)2) = 2.2 × 108 N/m2

Q. A steel rod has a radius $R = 9.5 mm$ and length $L = 81 c m$ . A force $F = 6.2 \times 1 0^{4} N$ stretches it along its length. What is the stress in the rod?

$0.95 \times 1 0^{8} N / m^{2}$

$1.1 \times 1 0^{8} N / m^{2}$

$2.2 \times 1 0^{8} N / m^{2}$

$3.2 \times 1 0^{8} N / m^{2}$

Stress $= \frac{F}{A}$
$= \frac{6.2 \times 1 0 ^{4}}{π r ^{2}}$
$= \frac{6.2 \times 1 0 ^{4}}{3.1 \times ( 9.5 ) ^{2} \times ( 1 0 ^{- 3} ) ^{2}}$
$= 2.2 \times 1 0^{8} N / m^{2}$

Q. A steel rod has a radius R=9.5mm and length L=81cm . A force F=6.2×104N stretches it along its length. What is the stress in the rod?

0.95×108N/m2

1.1×108N/m2

2.2×108N/m2

3.2×108N/m2