Answer:
(a) Precipitation hardening - 1, 2, 4
(b) Dispersion strengthening - 1, 3, 5
Explanation:
The correct options for each are shown as follows:
Precipitation hardening
From the first statement; Dislocation movement is limited by precipitated particles. This resulted in an expansion in hardness and rigidity. Precipitates particles are separated out from the framework after heat treatment.
The aging process occurs in the second statement; because it speaks volumes on how heated solutions are treated with alloys above raised elevated temperature. As such when aging increases, there exists a decrease in the hardness of the alloy.
Also, for the third option for precipitation hardening; This cycle includes the application of heat the alloy (amalgam) to a raised temperature, maintaining such temperature for an extended period of time. This temperature relies upon alloying components. e.g. Heating of steel underneath eutectic temperature. Subsequent to heating, the alloy is extinguished and immersed in water.
Dispersion strengthening
Here: The effect of hearting is not significant to the hardness of alloys hardening by the method in statement 3.
In statement 5: The process only involves the dispersion of particles and not the application of heat.
Answer:
The true stress necessary to plastically elongate the specimen is 406.69MPa
Explanation:
The Explanation or Solving is on the attached document.
Answer:
Water surface tension
Explanation:
The water around the paperclip forms a kind of elastic surface, deforming, in which the clip can stay afloat.
This is because the molecules that are on the surface of the water, already in contact with the air, try to cling to those that are next to them and those that are immediately below.
If we added even if it were just a drop of soap in the water, the clip would go to the bottom, because the soap has the ability to decrease the surface tension of the water.
Answer:
Mass of earth will be 
Explanation:
We have given acceleration due to gravity 
Radius of earth = 6370 km =
Gravitational constant 
We know that acceleration due to gravity is given by
, here G is gravitational constant, M is mass of earth and R is radius of earth
So 

So mass of earth will be 