Determine the critical crack length for a through crack contained within a thick plate of 7150-T651 aluminum alloy that is in uniaxial tension. For this alloy Kic = 24.7 MPa m1/2 and =395 MPa. Assume Y = . The answer should be in mm with 3 decimals of accuracy.

To solve this problem we will apply the concepts related to the fracture toughness of material that relates the nominal stress, half of the internal through crack and the dimensional geometric constant. The mathematical equation contained in this equation is,

Here,

= Fracture toughness of the material

= Applied nominal stress

a = Half of an internal through crack

Y = Dimensional geometric constant

Rearranging to find the crack length we have that

Our values,

Replacing with our values,

Calculate the critical crack length for a through crack in a thick plate,

Therefore the critical crack length for a through crack in a thick plate 0.79237mm

in physics zero. in muscle fatigue could be high

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s