For the following questions answer them individually
A spherical vessel with an inside diameter of 2 m is made of material having an allowable stress in tension of 500 kg/cm$$^2$$. The thickness of a shell to withstand a pressure of 50 kg/cm$$^2$$ should be
For best hydraulic rectangular cross-section of an open channel, its depth should be equal to
Compare the strengths of solid and hollow shafts both having outside diameter D and hollow shaft having inside diameter of $$\frac{D}{2}$$ in torsion. The ratio of strength of solid to hollow shafts in torsion will be
A heat engine is supplied heat at the rate of 30,000 J/s and gives an output of 9 kW. The thermal efficiency of engine will be
If a body is transmitting torque T kgm at angular speed of $$\theta$$ radians/sec, then h.p. transmitted will be