Answer:
i) S–N plot is attached
ii) fatigue strength = 100 MPa
iii) fatigue life = 5.62 x 10^(5) cycles
Explanation:
i) I have attached the S–N plot (stress amplitude versus logarithm of cycles to failure)
ii) The question says we should find the fatigue strength at 4 × 10^(6) cycles.
So let's find the log of this and trace it on the graph attached.
Log(4 × 10^(6)) = 6.6
From the graph attached, at log of cycle value of 6.6, the fatigue strength is approximately 100 MPa
iii) The question says we should find the fatigue life for 120 MPa.
Thus, from the graph, at stress amplitude of 120 MPa, the log of cycles is approximately 5.75.
Thus,the fatigue life will be the inverse log of 5.75.
Thus, fatigue life = 10^(5.75)
Fatigue life = 5.62 x 10^(5)
I think it’s is false I’m not that sure
Answer and Explanation:
The increase in entropy principle is defined as the process in which the total change in entropy of system with its adiabatic surroundings is always positive or equal to zero. The increase in entropy mostly takes place when a solid becomes liquid because randomness is increases when solid becomes liquid so entropy is also increases.
example of increase of entropy is when solid burns and become ash, ice melting
Answer:
a) 14.285
b) 8.956
Explanation:
Given :
The combustion of the ethanol is with air
Air is 21% oxygen
and, 79% nitrogen
thus, for 1 O₂ we have (79/21)N₂
thus,
the stochiometric equation for the combustion is as:
C₂H₅OH + 3[O₂ + (79/21)N₂] ⇒ 2CO₂ + 3H₂O + 3 × (79/21)N₂
Now,
the molecular weight of the fuel (C₂H₅OH) = (2× 12) + (5 × 1) + 16 + 1 = 46 g/mol
Molecular weight of the air = (2 × 16) + ((79/21) × 28) = 137.33 g/mol
a) air/fuel ratio on a molar basis
we have
air-fuel ratio = moles of air / moles of fuel
or
air-fuel ratio = [3 × 1 + 3 × (79/21)] / 1 = 14.285
b) air/fuel ratio on a mass basis = Mass of air / mass of fuel
or
air/fuel ratio on a mass basis = (number of moles of air × molar mass of air) / (number of moles of fuel × molar mass of fuel)
on substituting the values, we have
air/fuel ratio on a mass basis = (3 × 137.33) / (1 × 46) = 8.956