Answer Happy

A steel bar with a small crack in the centre expands as the temperature increases and it buckles as shown in the figure. Assume that the length of the bar L0​ is 4.55 m. Find the rise in the centre (x in the figure) for a temperature increase of 40.0∘C. (b) [10 marks] A cylindrical steel rod of length 1.6 m and cross-sectional area 4.2 cm2 is insulated along its side. One end of the rod is held in a water-ice mixture and the other end is in a mixture of boiling water and steam, so there is a temperature difference of 100∘C between the two ends. i) At what rate is energy conducted along the rod? ii) How long does it take to melt 15 g of ice? (c) [4 marks] State the First Law of Thermodynamics mathematically and in words. cp​=4.82 kJ kg−1 K−1 for water - assume constant with temperature. Freezing point of water =273 K Lmelt ​=334 kJ kg−1. Lvop ​=2.26MJkg−1 for water. Coefficient of linear expansion of steel is 11×10−6 K−1 Thermal conductivity of steel is 14 W m−1 K−1 Density of steel is 8.05×103 kg m−3