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Mechanical engineering Questions and solutions set - 7

Mechanical engineering Questions and solutions set - 7
Question:-
Option (A)
49.925 mm
Option (B)
50.00 mm
Option (C)
50.075 mm
Option (D)
None of the above
Correct Option:
D
Question Solution:
For blanking
Size of die = size of blank
Punch dia = size of blank -2C
C = 0.05 x 1.0 (Taking 5% clearance)
\ Punch dia = 50 – 2 x 0.05 = 49.9 mm
Hence, None of the above
Question:-
Option (A)
2000 K
Option (B)
4000 K
Option (C)
1000 K
Option (D)
16000 K
Correct Option:
A
Question Solution:
Heat flux = (Q/A) =q = sT4
90.72 x 104 = 5.67 x 10-8 x T4
T = 2000 K
Question:-
Option (A)
h1+h2 = K
Option (B)
h21 + h22 = K2
Option (C)
h1h2 = K2
Option (D)
Ö(h1h2) = K2
Correct Option:
C
Question Solution:
h1 h2 = K2
Question:-
Option (A)
30 MPa
Option (B)
60 MPa
Option (C)
90 MPa
Option (D)
120 MPa
Correct Option:
B
Question Solution:

60 MPa
Mohr circle for pure shear
So the compressive stress would be
equal to Applied shear stress
Question:-
Option (A)
Ö[(4k(r+a)2)/ (3mr2)]
Option (B)
Ö[(3K(r+a))/(4mr2)]
Option (C)
Ö[(3mr)/(4K(r+a)2)]
Option (D)
Ö[(4mr)/(3K(r+a))]
Correct Option:
A
Question Solution:

Taking moment about O
Iq +2K(r+a) q x (r+a)=0
Iq +2K(r+a)2 q =0
I for a disc rolling about surface
=(3/2)mr2
q + (2K(r+a)2/I) q =0
W=Ö[{2K(r+a)2/I}] = Ö[{2K(r+a)2}/{(3/2)mr2}]
W=Ö[{4K(r+a)2}/I]
Question:-
Option (A)
Large latent heat of vaporization and low operating pressures
Option (B)
Small latent heat of vaporization and high operating pressures.
Option (C)
Large latent heat of vaporization and large operating pressures
Option (D)
Small latent heat of vaporization and low operating pressures.
Correct Option:
A