Question

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

Answer 1

cross section area = 40.4 ×
`10^(-4)` m²

Step-by-step 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 =
`(\pi)/(4) d^2` ...................1

piston area =
`(\pi)/(4) 500^2`

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 =
`(force)/(cross\ section\ area)` .................3

area =
`(274889.356)/(68)`

area = 4042.4905 mm²

area = 40.4 ×
`10^(-4)` m²

so correct option is (A) 40.4 × 10.4 (