A rod of material A has a larger Youngs modulus than a rod o

A rod of material A has a larger Young\'s modulus than a rod of material B with the same dimensions. If the two rods are both loaded with the same force, A will stretch more than B B will stretch more than A A & B will stretch the same amount Can\'t tell from the information given The true stress on a part under tensile loading is always less than the engineering stress. True False Which polycrystalliuc material will show the largest % increase in yield strength when the grain diameter is reduced Copper Titanium Mild Steel Ni3AI For Oxygen free copper (figure 6.43) a yield strength of 40 ksi can result from 5% Cold Work 10% Cold Work 15% Cold Work 25% Cold Work Mechanical Properties Which alloys (in general) have a better resistance to fracture? Aluminum alloys Titanium alloys Steel alloys At a fatigue stress amplitude level of 15,000 psi 2014 Aluminum alloys will never fail in fatigue 1047 Steels will never fail in fatigue All materials will eventually fail in fatigue Neither material will ever fail in fatigue When designing against failure by creep, we keep in mind that A large change in temperature can lead to a small change in rupture time. A large change in rupture time will require a small change in temperature. A decrease in the applied stress level decreases the value of the LM parameter. None of the above are true Properties of Pure Substances Compressibility factor: Nitrogen is at 10 MPa and 150K. Determine the specific volume using the ideal gas equation and the compressibility factor. If the relative humidity of air at 23 degree C is 50%, determine the partial pressure of the water vapor. The pressure in the room is 101.3 kPa. What amount of heat needs to be removed to lower the temp to 20C and lower humidity to 40% if the air is flowing at 1000 CFM. Introduction to fluid mechanics Kerosene at 20 degree C is placed in a capillary tube (diameter = 1mm) exposed to air. If the contact angle is

Solution

>> Solution 21

Now, according to Hooke\'s Law

Stress = Young\'s Modulud*Strain

Now, Dimensions and loading are same

So, Stress will be same in both cases

>> As, Young\'s Modulus of A is greater than B

So, Strain of B is more than A

>> Now, as Strain = Change in Length/Original Length

So, B will stretch more than A ......OPTION (b) ...

>> Solution 22

rAs, TRue Stress = Load/Actual Area

whereas, Engineering Stress Load/Initial Area

>> Now, as Actual area is decreasing as the process goes on

So, True stress will be more than Engineering Stress ...........OPTION(b) .....

>> Solution 23

As, Yield strength of material having smallest crystal size will show maximum increase when grain diameter is reduced

So, Option(c) is correct

>> Solution 25

Aluminium alloys have a better resistance to fracture due o more ductile behaviour shown by aluminium

So, OPTION (a) is answer.....