29) When a shaft is subjected to a twisting moment, every cross-section of the shaft will be under

30) A bar of length L meters extends by l mm under a tensile force of P. The strain produced in the bar is

31) A piece of wood having weight 5 kg floats in water with 60% of its volume under the liquid. The specific gravity of wood is

32) The unit of radio-activity is

33) In an application, the bearing is subjected to radial as well as axial loads. Which type of rolling contact bearings you would suggest?