Answer:
Correct option a) True.
Explanation:
It is true since the Vickers hardness value refers to the force applied in a 136 ° diamond tip penetrator divided by the surface of the groove produced in the material, the lower the impression made on this greater the value will be end of the Vickers measurement and greater its hardness.
The equation to determine the Vickers hardness value will be:
Hv= ((1.854 × P)/(d²)) (kg/mm²)
Therefore a value of 220 Vickers refers to a harder material than another value of 180 Vickers.
Answer:
The 5/16 – 24 UNF is stronger because it has more tensile load capacity.
Tensile load capacity for M8 -1.25 = 5670 lb
Tensile load capacity for M8 -1 = 6067 lb
Explanation:
For 5/16 - 18 UNC thread:
D = 0.3125
n = 18
Therefore the tensile load capacity is = 100000 X (0.7854 X (0.3125 - 0.9743/ 18) ^2
= 5243 lb.
Similarly for 5/16 - 24 UNF , only the n value changes to 24
we get the tensile load capacity = 5806.6 lb
Hence the 5/16 – 24 UNF is stronger because it has more tensile load capacity.
For metric Bolts:
We have to consider all values in SI units
Strength = 689 MPa
We get for M8 -1.25:
Tensile load capacity as = 689 X 36.6 = 25223 N = 5670 lb
For M8 -1:
Tensile load capacity as = 689 X 39.167 = 26986 N = 6067lb
Answer:
Maximum shear stress is;
τ_max = 1427.12 psi
Explanation:
We are given;
Power = 2 HP = 2 × 746 Watts = 1492 W
Angular speed;ω = 450 rev/min = 450 × 2π/60 rad/s = 47.124 rad/s
Diameter;d = 1 in
We know that; power = shear stress × angular speed
So,
P = τω
τ = P/ω
τ = 1492/47.124
τ = 31.66 N.m
Converting this to lb.in, we have;
τ = 280.2146 lb.in
Maximum shear stress is given by the formula;
τ_max = (τ•d/2)/J
J is polar moment of inertia given by the formula; J = πd⁴/32
So,
τ_max = (τ•d/2)/(πd⁴/32)
This reduces to;
τ_max = (16τ)/(πd³)
Plugging in values;
τ_max = (16 × 280.2146)/((π×1³)
τ_max = 1427.12 psi
Answer:
Q=36444.11 Btu
Explanation:
Given that
Initial temperature = 60° F
Final temperature = 110° F
Specific heat of water = 0.999 Btu/lbm.R
Volume of water = 90 gallon
Mass = Volume x density
Mass ,m= 90 x 0.13 x 62.36 lbm
m=729.62 lbm
We know that sensible heat given as
Q= m Cp ΔT
Now by putting the values
Q= 729.62 x 0.999 x (110-60) Btu
Q=36444.11 Btu
