Answer:
Explanation:
Given data in question
mean stress = 50 MPa
amplitude stress = 225 MPa
to find out
maximum stress, stress ratio, magnitude of the stress range.
solution
we will find first maximum stress and minimum stress
and stress will be sum of (maximum +minimum stress) / 2
so for stress 50 MPa and 225 MPa
=
+
/ 2
50 =
+
/ 2 ...........1
and
225 =
+
/ 2 ...........2
from eqution 1 and 2 we get maximum and minimum stress
= 275 MPa ............3
and
= -175 MPa ............4
In 2nd part we stress ratio is will compute by ratio of equation 3 and 4
we get ratio =
/
ratio = -175 / 227
ratio = -0.64
now in 3rd part magnitude will calculate by subtracting maximum stress - minimum stress i.e.
magnitude =
-
magnitude = 275 - (-175) = 450 MPa
Answer:
a) Q = 251.758 kJ/mol
b) creep rate is 
Explanation:
we know Arrhenius expression is given as

where
Q is activation energy
C is pre- exponential constant
At 700 degree C creep rate is
% per hr
At 800 degree C creep rate is
% per hr
activation energy for creep is
= 
![\frac{1\%}{5.5 \times 10^{-2}\%} = e^{[\frac{-Q}{R(800+273)}] -[\frac{-Q}{R(800+273)}]}](https://tex.z-dn.net/?f=%5Cfrac%7B1%5C%25%7D%7B5.5%20%5Ctimes%2010%5E%7B-2%7D%5C%25%7D%20%3D%20e%5E%7B%5B%5Cfrac%7B-Q%7D%7BR%28800%2B273%29%7D%5D%20-%5B%5Cfrac%7B-Q%7D%7BR%28800%2B273%29%7D%5D%7D)
![\frac{0.01}{5.5\times 10^{-4}} = ln [e^{\frac{Q}{8.314}[\frac{1}{1073} - \frac{1}{973}]}]](https://tex.z-dn.net/?f=%5Cfrac%7B0.01%7D%7B5.5%5Ctimes%2010%5E%7B-4%7D%7D%20%3D%20ln%20%5Be%5E%7B%5Cfrac%7BQ%7D%7B8.314%7D%5B%5Cfrac%7B1%7D%7B1073%7D%20-%20%5Cfrac%7B1%7D%7B973%7D%5D%7D%5D)
solving for Q we get
Q = 251.758 kJ/mol
b) creep rate at 500 degree C
we know





Answer:
A civil engineer.
Explanation:
Civil engineering is the science that deals with the design, creation and maintenance of constructions for civil use on the earth's surface. Thus, this specialty seeks to adapt soils to the needs of life in society, creating buildings, bridges, and all other constructions adapted to civil life, while taking care of the correct use of soils and the correct distribution of spaces and resources. to be used for such constructions.
Answer:
because burning rubber increases the grip power