Answer:
The Euler buckling load of a 160-cm-long column will be 1.33 times the Euler buckling load of an equivalent 120-cm-long column.
Explanation:
160 - 120 = 40
120 = 100
40 = X
40 x 100 / 120 = X
4000 / 120 = X
33.333 = X
120 = 100
160 = X
160 x 100 /120 = X
16000 / 120 = X
133.333 = X
C. seems like the best answer. i may be wrong so don’t quote me on that
In order to develop this problem it is necessary to take into account the concepts related to fatigue and compression effort and Goodman equation, i.e, an equation that can be used to quantify the interaction of mean and alternating stresses on the fatigue life of a materia.
With the given data we can proceed to calculate the compression stress:



Through Goodman's equations the combined effort by fatigue and compression is expressed as:

Where,
Fatigue limit for comined alternating and mean stress
Fatigue Limit
Mean stress (due to static load)
Ultimate tensile stress
Security Factor
We can replace the values and assume a security factor of 1, then

Re-arrenge for 

We know that the stress is representing as,

Then,
Where
=Max Moment
I= Intertia
The inertia for this object is

Then replacing and re-arrenge for 



Thereforethe moment that can be applied to this shaft so that fatigue does not occur is 3.2kNm
Answer:
1425.78 N.m
Explanation:
Moments of force is calculated as ;
Moments= Force * distance
M= F*d
The S.I unit for moment of force is Newton-meter (N.m)
Given in the question;
Force = 72 lbs
1 pound = 4.45 N
72 lbs = 4.45 * 72=320.4 N
Distance= 15 ft
1ft= 0.3048 m
15 ft = 15*0.3048 = 4.57 m
d= 4.57 m
M= F*d
M=320.4*4.57 =1425.78 N.m