The 6kg box is pushed to the left at a constant speed. The coefficient of friction is 0.78. Solve for the amount of force with w
1 answer:
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Answer:
The critical stress required for the propagation of an initial crack = 21.84 M pa
Explanation:
Given data
Modulus of elasticity E = 225 ×
Specific surface energy for magnesium oxide is = 1
Crack length (a) = 0.3 mm = 0.0003 m
Critical stress is given by =
-------- (1)
⇒ 2 E = 2 × 225 ×
× 1 = 450 ×
⇒ a = 3.14 × 0.0003 = 0.000942
⇒ Put these values in equation 1 we get
⇒ =
⇒ = 4.77 ×
⇒ = 2.184 ×
⇒ = 21.84
⇒ = 21.84 M pa
This is the critical stress required for the propagation of an initial crack.