Answer:
a) Under damped
Explanation:
Given that system is critically damped .And we have to find out the condition when gain is increased.
As we know that damping ratio given as follows

Where C is the damping coefficient and Cc is the critical damping coefficient.

So from above we can say that


From above relationship we can say when gain (K) is increases then system will become under damped system.
The pressure of water is 7.3851 kPa
<u>Explanation:</u>
Given data,
V = 150×

m = 1 Kg
= 2 MPa
= 40°C
The waters specific volume is calculated:
= V/m
Here, the waters specific volume at initial condition is
, the containers volume is V, waters mass is m.
= 150×
/1
= 0.15
/ Kg
The temperature from super heated water tables used in interpolation method between the lower and upper limit for the specific volume corresponds 0.15
/ Kg and 0.13
/ Kg.
= 350+(400-350) 
= 395.17°C
Hence, the initial temperature is 395.17°C.
The volume is constant in the rigid container.
=
= 0.15
/ Kg
In saturated water labels for
= 40°C.
= 0.001008
/ Kg
= 19.515
/ Kg
The final state is two phase region
<
<
.
In saturated water labels for
= 40°C.
=
= 7.3851 kPa
= 7.3851 kPa
Force P is 11304 N and normal stress is 400 N/mm²
<u>Explanation:</u>
Given-
Length, l = 9 m = 9000 mm
Diameter, d = 6 mm
Radius, r = 3 mm
Stretched length, Δl= 18 mm
Modulus of elasticity, E = 200 GPa = 200 X 10³MPa
Force, P = ?
According to Hooke's law,
Stress is directly proportional to strain.
So,
σ ∝ ε
σ = E ε
Where, E is the modulus of elasticity
We know,
ε = Δl / l
So,
σ = E X Δl/l
σ =

We know,
σ = P/A
And A = π (r)²
σ = P / π (r)²

Therefore, Force P is 11304 N and normal stress is 400 N/mm²