Mechanical Engineering Answers

A dc shunt motor is driving a constant-torque load at the rated speed and rated terminal voltage. The motor has the following rated data:


Terminal voltage = 115 V


Speed = 312 rpm


Field constant K(phi) = 3 V sec


If the terminal voltage of the motor is reduced by 10%, what is the motor speed? Assume that the field voltage is also reduced by the same ratio.

PET has a Young's, Modulus of 3.5 GPa and PLGA 1.2 GPa. A polymer blend is prepared with 50:50 mixture (PET:PlGA) . What is the Young's, Modulus of this blend (use mixture rule). Calculate the percent load borne by PET when the blend is subjected to a load. If after 10 days, half of PET and one third of PLGA had degraded, what is the Young's Modulus of this blend.

what is the meaning of white circle and black circle in Table 5 of standard IS1367 part 3.

The pressure difference p of air that flows through a fan is a function of the diameter D of the blade, its angular rotation, density of the air, and the flow Q. Use the FLT method of repeating variables to generate a dimensionless relationship between these parameters

Describe and explain the working of a Geiger-Muller (G.M.) tube.

steam at 7bar and 250 C enters a pipeline and flow along it at constant pressure. if the stream rejects heat steadily to the surroundings. at what temperature will droplets of water begin to form in the vapour ?. using steady flow energy equation and neglecting changes in the velocity. calculate the heat rejected per kilogram of steam flow

A simply supported bridge shows below is the primary path for the village people

to travel to the city centre. In the following case, the loading from the bus (5000

kg) and truck (3000 kg) can be treated as concentrated loads and the three private

cars (1500 kg each) can be treated as evenly distributed load. Your supervisor asks

you to find out the reaction forces in both simply supported at the end of the

bridge

Air and fuel enter a furnace used for home heating. The air has an enthalpy of 320 kJ/kg and the fuel has an enthalpy of 43027 kJ/kg. The gases leaving the furnace has an enthalpy of 616 kJ/kg. There are 17 kgair/kgfuel, water circulated through the wall furnace receiving heat. The hose required 17.02 kW of heat, what is the fuel consumption per day. (41 kg/day)

The exhaust gas leaving an oil engine is passed through a heat exchanger which

consist of tubes surrounding by water. The gas enters at 327 oC and leaves at 193

oC. The water enters the exchanger at 17 and leaves at 56 oC. If the mass flow rate

of water is 2.54kg/min. Determine the mass flow rate of gas, take cp of the gas is

1.04 kJ/kg.

Calculate the internal energy and the enthalpy of 1 kg of air occupying 0.05 m3

at

20 oC at 20 bar. If the internal energy is increased by 120 kJ as the air compressed

to 50 bar. Calculate the new volume occupied by 1 kg of air.