Answer:
Planes can fly because they have wings and jet turbines and boats cant they need wings and planes cant float because there is to much weight
Answer:
B A and C
Explanation:
Given:
Specimen σ
σ
A +450 -150
B +300 -300
C +500 -200
Solution:
Compute the mean stress
σ
= (σ
+ σ
)/2
σ
= (450 + (-150)) / 2
= (450 - 150) / 2
= 300/2
σ
= 150 MPa
σ
= (300 + (-300))/2
= (300 - 300) / 2
= 0/2
σ
= 0 MPa
σ
= (500 + (-200))/2
= (500 - 200) / 2
= 300/2
σ
= 150 MPa
Compute stress amplitude:
σ
= (σ
- σ
)/2
σ
= (450 - (-150)) / 2
= (450 + 150) / 2
= 600/2
σ
= 300 MPa
σ
= (300- (-300)) / 2
= (300 + 300) / 2
= 600/2
σ
= 300 MPa
σ
= (500 - (-200))/2
= (500 + 200) / 2
= 700 / 2
σ
= 350 MPa
From the above results it is concluded that the longest fatigue lifetime is of specimen B because it has the minimum mean stress.
Next, the specimen A has the fatigue lifetime which is shorter than B but longer than specimen C.
In the last comes specimen C which has the shortest fatigue lifetime because it has the higher mean stress and highest stress amplitude.
Answer:
The answer is "
".
Explanation:
The amount of kilograms, which travel in a thick sheet of hydrogen:


calculating the value of 


calculating the value of 




Answer:
4.26
Explanation:
The wavelength λ is given by:

Phase constant (β) = 2π/λ
βl = 2π/λ × l
l = 2 cm = 0.02 m
βl = 2π/0.0625 × 0.02=2.01 rad = 115.3°
1 rad = 180/π degrees
