A steel rod is heated from 25 to 250 degree Celsius. Its coefficient of thermal expansion is 10-5 and E = 100 GN/m². if the rod is free to expand, the thermal stress developed in it is: a) 100 kN/m² b) 240 kN/m² c) Zero d) Infinity

give 5 important concepts you’ve learned in kinetics of particles (engineering mechanics 2)

A circular log floating in water is neutrally buoyant. Our ancestors found that by having half a log with semi-circular cross section and hollowing out the interior, it became stable so that they could use it to migrate across oceans. The reasons for it to become stable are: (i) (ii) (iii) (iv) It lowers the centre of gravity G so that it is below the centre of buoyancy B. It lowers the centre of gravity G so that it is below the metacentre M. It increases the metacentric radius BM. It enables the shifting of the centre of buoyancy B laterally to produce a restoring moment when it is tilted. (A) (B) (C) (D) (i) and (ii) (ii) and (iii) (iii) and (iv) (iv) and (i)

An electric hot water heater consumes 3.1 kilowatts of electricity and converts it to heat. How long will it take the water heater to heat a 67 gallon tank of water from 10 degrees Celsius to 50 degrees Celsius? (1 kilogram of water is 0.37 gallons, 1 Calorie = 4200 J).  It may be helpful to refer back to the weekly handout for guidance on this problem. Your final answer should be in minutes (rounded to the nearest 10 minutes).