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The piston of a steam engine is S0 cm in diameter, and the maximum steam gage pressure is 1.4 MPa. If the design stress for the piston rod is 68 MPa, its cross-sectional area (m') should be most nearly:

(A) 40.4 × 10.4 (

B) 98.8 x 104

(C) 228.0x 10

(D) 323.0 x 10

Respuesta :

Answer:

cross section area = 40.4 × [tex]10^{-4}[/tex] m²

Explanation:

given data

diameter = 50 cm = 500 mm

maximum steam gage pressure = 1.4 MPa

design stress = 68 MPa

to find out

cross-sectional area

solution

we get here piston area that is

piston area = [tex]\frac{\pi}{4} d^2[/tex]   ...................1

piston area = [tex]\frac{\pi}{4} 500^2[/tex]

piston area = 196349.54 mm²

and we know force is express as  

force  is = pressure × piston area    ............................2

force  is = 1.4 × 196349.54

force = 274889.356 N

and stress is express as

stress = [tex]\frac{force}{cross\ section\ area}[/tex]    .................3

area = [tex]\frac{274889.356}{68}[/tex]

area = 4042.4905 mm²

area = 40.4 × [tex]10^{-4}[/tex] m²

so correct option is (A) 40.4 × 10.4 (

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