A null ray approaching a distant astronomical source appears to slow down, while a massive particle speeds up in accordance with Newtonian gravitation. The integration of these apparently incompatible aspects of motion in general relativity is due to the existence of a critical speed. Dynamics of particles moving faster than the critical speed could then be contrary to Newtonian expectations. W...

Data from storms suggest that the critical wind speed at which trees break is constant (≃42m/s), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic propertie...

The pressure to achieve a higher speed of train operation has increased in the last few years due development high-speed railway lines. In presence soft soils, this increase is not possible without undertaking soil improvement measures, since critical lower than desired operation. One most widely used techniques that stone columns. relation these concept length which, up now, only been studied ...

In this paper, classical thin shell theory is used to analyze vibration and critical speed of simply supported rotating orthotropic cylindrical shell. The effects of centrifugal and Coriolis forces due to the rotation are considered in the present for‌mulation.. In addition, axial load is applied on cylinder as a ratio of critical buckling load. Finally the effects of orthotropic ratio, materia...