ME 12 Assignment No. 1
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This document contains a thermodynamics assignment with 10 problems related to concepts like specific weight, acceleration due to gravity at different elevations, pressure and force exerted by fluids, density and specific volume of mixtures, heat transfer between materials, mass and energy balances, and work calculations for steam turbines. Students are asked to solve these 10 problems and submit their solutions to the given email address by the provided due date.
ME 12 Assignment No. 1
- 1. ME 12 f1 THERMODYNAMICS ASSIGNMENT NO.1 Due Date: ___________ Name __________________________ PROBLEM SOLVING 1. A cubic meter of water at room temperature has weight of 9.8 KN at a location where g = 9.8 m/sec2 . What is its specific weight at a location where g = 9.77 m/sec2 . 2. The acceleration of gravity is given as function of elevation above sea level by the relation g = 9.81- 3.32 x 10-6 h m/sec2 , with h measured in meters. What is the weight of an airplane at 10 km elevation when its weight at sea level is 40 KN. 3. A) What is the total or absolute pressure on the back of a scuba diver in a lake at a depth 8 m? B) What is the force on the divers back due to the water alone, taking the surface of the back to be a rectangle 60 cm x 50 cm. 4. A mercury barometer at the ground floor of Kingston Tower in Chicago reads 735 mm Hg. At the same time another barometer at the top of the tower reads 590 mmHg. Assuming the air to be constant at 1.21 kg/m3 , what is the approximate height of the tower using g = 9.7 m/sec2 . 5. A tank contains a mixture of 20 kg of nitrogen and 20 kg of carbon monoxide. The total tank volume is 20 m3 . Determine the density, specific volume and specific weight of the mixture if local g = 9,81 m/sec2 . 6. A block of aluminum 10 cm on a side is cooled from 100C to 20C. If the energy removed from the aluminum block were added to a copper block of similar dimensions at 20C , what would be the final temperature of the copper block be? (al= 2700 kg/m3 ; copper = 8900 kg/m3 ) 7. How many kilograms of aluminum will experience the same temperature rise as 3 kg of copper when the same amount of heat is added to each? (Cal = 0.896 KJ/kg-K; Ccopper = 0.383 KJ/kg-K) 8. A certain fluid is flowing in a 0.5 m x 0.3 m channel at the rate of 3 m3 /sec and has a specific volume of 0.0012 m3 /kg. Determine the mass flow rate of water flowing in kg/sec. 9. Steam expands in a nozzle fro an initial conditions of 2.8 MPa and 240C (h = 2834.48 KJ/kg; = 0.0746 m3 /kg) to a pressure of 140 KPa (h = 2320 KJ/kg; = 1.045 m3 kg). For a mass flow rate of 2 kg/sec and neglecting the velocity at inlet determine the velocity and the diameter at exit. 10.Steam flows steadily through a turbine with a mass flow rate of 2.5 kg/sec. The inlet steam conditions are, P = 7000 KPa; t = 500C; h = 3410.3 KJ/kg and at exit P = 20 KPa; t = 60.6C; h = 2239.45 KJ/kg.The inlet is 3 m higher than its outlet. Assuming no heat losses determine the actual work developed by the turbine if mechanical losses amounts to 10%. Due Date _________________ Send your solutions to: ymelliza@xu.edu.ph