Consider a beam with circular cross-section of diameter $$d.$$ The ratio of the second moment of area about the neutral axis to the section modulus of the area is

An initially stress-free massless elastic beam of length $$L$$ and circular cross-section with diameter $$d (d < < L)$$ is held fixed between two walls as shown. The beam material has Young's modulus $$E$$ and coefficient of thermal expansion $$\alpha .$$

If the beam is slowly and uniformly heated, the temperature rise required to cause the beam to buckle is proportional to

A motor driving a solid circular steel shaft transmits $$40$$ $$kW$$ of power at $$500$$ $$rpm$$. If the diameter of the shaft is $$40$$ $$mm,$$ the maximum shear stress in the shaft is ________ $$MP$$a.

In an epicyclic gear train, shown in the figure, the outer ring gear is fixed, while the sun gear rotates counterclockwise at 100 rpm. Let the number of teeth on the sun, planet and outer gears to be 50, 25 and 100, respectively. The ratio of magnitudes of angular velocity of the planet gear to the angular velocity of the carrier arm is _________.