Answer:
The maximum length of a surface flaw is 8.24 μm
8.24 μm
Explanation:
Given that:
The modulus of elasticity E = 69 GPa
The specific surface energy 
= 0.3 J/m²
The length of the surface flaw "a" = ??
From the theory of the brittle fracture;
Making a the subject of the formula; we have:
a = 8.24 × 10⁻⁶ m
a = 8.24 μm
Thus; the maximum length of a surface flaw is 8.24 μm
Answer:
a. Fraction of Atom = 2.41E-5 when T = 600K
b. Fraction of Atom = 5.03E-10 when T = 298K
Explanation:
a.
Given
T = Temperature = 600K
Qv = Energy for formation = 0.55eV/atom
To calculate the fraction of atom sites, we make use of the following formula
Nv/N = exp(-Qv/kT)
Where k = Boltzmann Constant = 8.62E-5eV/K
Nv/N = exp(-0.55/(8.62E-5 * 600))
Nv/N = 0.000024078672493307
Nv/N = 2.41E-5
b. When T = 298K
Nv/N = exp(-0.55/(8.62E-5 * 298))
Nv/N = 5.026591237904E−10
Nv/N = 5.03E-10 ----- Approximated
Answer:
Highest temperature rise allowable = ΔT = 21.22°C
Highest allowable temperature = ΔT + 20 = 41.22°C
Explanation:
From literature, the coefficient of volume expansion of water between 20°C and 50°C = β = (0.377 × 10⁻³) K⁻¹
Volume expansivity is given by
ΔV = V β ΔT
ΔV = Change in volume
V = initial volume
β = Coefficient of volume expansion = (0.377 × 10⁻³) K⁻¹ = 0.000377 K⁻¹
ΔT = Change in temperature = ?
It is given in the question that maximum volume increase the tank can withstand is
(ΔV/V) × 100% = 0.8%
(ΔV/V) = 0.008
V β ΔT = ΔV
β ΔT = (ΔV/V)
β ΔT = 0.008
ΔT = (0.008/β)
ΔT = (0.008/0.000377)
ΔT = 21.22°C
Highest temperature rise allowable = ΔT = 21.22°C
Highest allowable temperature = ΔT + 20 = 41.22°C
Hope this Helps
Answer: D. Many more people crossed the mountains and settled between the Appalachians and the Mississippi
Explanation:
It was quite difficult to cross the Appalachian mountains at the time of the American colonies which led to the colonies being confined to the east of it.
This was until the late 1700s when Daniel Boone and a team of explorers heard that a path existed through the Appalachians and had been used by natives for a long time. After discovering this ''gap'' which was then named after an English prince, many more people were able to use it to settle more to the west of the continent.
