Answer:

So, Ma < 1 Flow is Subsonic
Explanation:
Mach Number:
Mach Number is the ratio of speed of the object to the speed of the sound. It is used to categorize the speed of the object on the basis of mach number as sonic, supersonic and hyper sonic. (It is a unit less quantity)
Mach < 1 Subsonic
Mach > 1 Supersonic
Ma= Speed of the object/Speed of the sound

So, Ma < 1 Flow is Subsonic
Answer:
Circular tube
Explanation:
Now for better understanding lets take an example
Lets take
Diameter of solid bar=
cm
Outer diameter of tube =6 cm
Inner diameter of tube=2 cm
So from we can say that both tubes have equal cross sectional area.
We know that buckling load is given as
If area moment of inertia(I) is high then buckling load will be high.
We know that area moment of inertia(I)
For circular tube 
For circular bar
Now by putting the values
For circular tube 
For circular bar 
So we can say that for same cross sectional area the area moment of inertia(I) is high for tube as compare to bar.So buckling load will be higher in tube as compare to bar.
Answer:
go on google and type NCEER book answers
The answer for this question is A
Answer:
The minimum volume requirement for the granite stones is 1543.64 cm³
Explanation:
1 granite stone weighs 10 denarium
100 granted stones will weigh 1000 denarium
1 denarium = 3.396g
1000 denarium = 3396g.
But we're told that 20% of material is lost during the making of these stones.
This means the mass calculated represents 80% of the original mass requirement, m.
80% of m = 3396
m = 3396/0.8 = 4425 g
This mass represents the minimum mass requirement for making the stones.
To now obtain the corresponding minimum volume requirement
Density = mass/volume
Volume = mass/density = 4425/2.75 = 1543.64 cm³
Hope this helps!!!