Answer:
The true stress required = 379 MPa
Explanation:
True Stress is the ratio of the internal resistive force to the instantaneous cross-sectional area of the specimen. True Strain is the natural log to the extended length after which load applied to the original length. The cold working stress – strain curve relation is as follows,
σ(t) = K (ε(t))ⁿ, σ(t) is the true stress, ε(t) is the true strain, K is the strength coefficient and n is the strain hardening exponent
True strain is given by
Epsilon t =㏑ (l/l₀)
Substitute㏑(l/l₀) for ε(t)
σ(t) = K(㏑(l/l₀))ⁿ
Given values l₀ = 49.7mm, l =51.7mm , n =0.2 , σ(t) =379Mpa
379 x 10⁶ = K (㏑(51.7/49.7))^0.2
K = 379 x 10⁶/(㏑(51.7/49.7))^0.2
K = 723.48 MPa
Knowing the constant value would be same as the same material is being used in the second test, we can find out the true stress using the above formula replacing the value of the constant.
σ(t) = K(㏑(l/l₀))ⁿ
l₀ = 49.7mm, l = 51.7mm, n = 0.2, K = 723.48Mpa
σ(t) = 723.48 x 106 x (㏑(51.7/49.7))^0.2
σ(t) = 379 MPa
The true stress necessary to plastically elongate the specimen is 379 MPa.
Answer:
<em>When salt is dissolved in water</em>, many physical properties change, among them the so called colligative properties:
- The vapor pressure of water decreases,
- The boiling point increases,
- The freezing point decreases, and
- Osmotic pressure appears.
Explanation:
Colligative properties are the physical properties of the solvents whose change is determined by the number of particles (moles or ions) of the solute added.
The colligative properties are: vapor pressure, boiling point, freezing point, and osmotic pressure.
<u>Vapor pressure</u>:
The vapor pressure is the pressure exerted by the vapor of a lquid over its surface, in a closed vessel.
The vapor pressure increases when a solute is added, because the presence of the solute causes less solvent molecules to be near the surface ready to escape to the vapor phase, which means that the vapor pressure is lower.
<u>Boiling point</u>:
The boiling point is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure. Since we have seen that the vapor pressure of water decreases when a solute occupies part of the surface, now more temperature will be required for the water molecules reach the atmospheric pressure. So, the boiling point increases when salt is dissolved in water.
<u>Freezing point</u>:
The freezing point is the temperarute at which the vapor pressure of the liquid and the solid are equal. Since, the vapor pressure of water with salt is lower than that of the pure water, the vapor pressure of the liquid and solid with salt will be equal at a lower temperature. Hence, the freezing point is lower (decreases).
<u>Osmotic pressure</u>:
Osmotic pressure is the additional pressure that must be exerted over a solution to make that the vapor pressure of the solvent in the solution equals the vapor pressure of the pure solvent. This additional pressure is proportional to the concentration of the solute: the higher the salt concentration the higher the osmotic pressure.
Answer:
<h2>A star's life cycle is determined by its mass. The larger its mass, the shorter its life cycle. A star's mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born. ... As the gas spins faster, it heats up and becomes as a protostar.</h2>
Explanation:
<h2>Read this and then choose your options ✍️✍️</h2>
There are more oxygen atoms in the reactants while there are less oxygen atoms in the product.
Both sides of the equation is supposed to be balanced for a balanced equation. If any one of them isn't balanced, the equation remains unbalanced.
The main reason why the reaction above can not be balanced is:
This chemical reaction SO2 + H2O -> H2SO2 is not correctly written.
It must be: SO2 + H2O -> H2SO3
<em>hope this helps....</em>
Answer:
Weather, environment, ecosystem, species, rain forests
Explanation:
