Hmm doesnt soujd familiar
Answer:
The correct answer is 231 Mpa i.e option a.
Explanation:
using the equation of torsion we Have

where,
= shear stress at a distance 'r' from the center
T = is the applied torque
= polar moment of inertia of the section
r = radial distance from the center
Thus we can see that if a point is located at center i.e r = 0 there will be no shearing stresses at the center due to torque.
We know that in case of a circular section the maximum shearing stresses due to a shear force occurs at the center and equals

Applying values we get

Because other scientists and science in general rely on their collegues' research which in turn allows development of our knowledge on the given subject. The more dont-to-earth reason may be safety. If someone performs an experiment without knowledge of its true results it might result in some danger to the safety of those perforning it without knowledge of all the risks.