Answer:
Hello your question lacks some vital parts here is the complete question
Determine Er(10) for this material (in Mpa) If the initial stress level was 2.76 Mpa (400psi) which dropped to 1.72 Mpa(250psi) after 60s
Answer: Er(10) for the material = 2.55 / 0.69 = 3.695 ≈ 3.70 Mpa
Explanation:
The equation of stress decay for viscoelastic polymers
equation 1
t = elapsed time = 60s
T = relaxation time
input the given values into the equation
1.72 = 2.76 exp ( -
exp ( - 60/T ) = 1.72/2.76 therefore T = 126.87S
Considering 10s for t
taking Ln of both sides of the equation
Ln
therefore = 370 psi
To determine the Er(10) for the material in (Mpa) we apply the relaxation modulus equation
Er(t) =
where Eo = strain level = 0.69
Er(t) = E(10)
= 2.55 Mpa
input this variables into equation
Er(10) for the material = 2.55 / 0.69 = 3.695 ≈ 3.70 Mpa
Answer:
A) 2P/(¶r^2)
B) p/(¶r^2)
Explanation:
Force = P
Radius = r
Area on which force acts = ¶r^2
If both forces are applied, total stress will be
S = 2P/(¶r^2)
When only one of the force is applied
S = p/(¶r^2)
Answer:
0.0002778° are equivalent to one second of arc.
Explanation:
1 degree consists of 60 arc minutes.
1 arc minutes consists of 60 arc seconds.
It can also be written as:
1 minute of arc comprise of 1/60 degree.
1 second of arc comprise of 1/60 arc minutes.
So,
<u>1 second of arc comprise of (1/60)*(1/60) degree.</u>
Thus,
Thus,
<u>0.0002778° are equivalent to one second of arc.</u>