Answer:
minimum length of a surface crack is 15.043 mm
Explanation:
given data
strain fracture toughness K = 78 MPa
tensile stress = 345 MPa
Y = 1.04
to find out
minimum length of a surface crack
solution
we find here length of critical interior flaw from formula that is
α =
....................1
put here value we get
α = 
α = 15.043 mm
so minimum length of a surface crack is 15.043 mm
Answer:
Tension in cable BE= 196.2 N
Reactions A and D both are 73.575 N
Explanation:
The free body diagram is as attached sketch. At equilibrium, sum of forces along y axis will be 0 hence
hence

Therefore, tension in the cable, 
Taking moments about point A, with clockwise moments as positive while anticlockwise moments as negative then



Similarly,


Therefore, both reactions at A and D are 73.575 N
C is your answers!!!!!$3&2)//