Engineering Answers

¨Water flows through a pipe AB of diameter d1 = 50 mm, which is in series with a pipe BC of diameter d2 = 75 mm in which the mean velocity v2 = 2 m/s. At C the pipe forks and one branch CD is of diameter d3 such that the mean velocity v3 is 1.5 m/s. The other branch CE is of diameter d4 = 30 mm and conditions are such that the discharge Q2 from BC divides so that Q4 = ½ Q3. Calculate the values of Q1,v1,Q2,Q3,D3,Q4 and v4..

3. For the magnetic circuit shown in figure 21.19 the reluctance of the central limb (PS) is 10 × 105 AT/Wb and the reluctance of the outer limbs (PTS and PQS) are same and equal to 15 × 105 AT/Wb. To produce 0.5 mWb in PQS, the mmf to be produced by the coil is: (A) 750 AT (B) 1750 AT (C) 250 AT (D) 1500 AT.

A new machine will cost $25,000. The machine is expected to last 4 years and has no salvage value. If the interest rate is 12%, determine the return and the risk associated with the purchase. Use present worth analysis.

Probability

0.3

0.4

0.3

Annual savings

$7,000

$8,500

$9,500

Animal Inheritance

Implement the following class hierarchy, the inheritance access level should be public for all the descendent classes.

1. Add a protected data member named id of integer type to Animal class.

2. Add get/set methods for id data member in Animal class with public access.

3. Add a default constructor to each of the above created class. The constructor should initialize the id data member of Animal, Reptile, Bird and Mammal,to 0, 1, 2 and 3 respectively also it display a message “(class Name)’s default constructor”.

4. Add a parameterized constructor to each of the above created class. The constructor should initialize the id data member of Animal, Reptile, Bird and Mammal, to the specified id passed to the constructor as an argument ,also it display a message “(class Name)’s default constructor”. The parameterized constructor should call its base class parameterized constructor to initialize any data member inherited from the base class.

A boiler produces 9000 kg of steam while I tonne of coal is burnt. The steam is produced at 10 bar from water at 15^ prime prime c The dryness fraction of steam is 0.9. Determine the efficiency of the boiler when the calorific value of the coal is 32 000 kJ/kg [Ans. 70.65%]

minimized the following boolean expression using K-map and boolean algebra. Draw the schematic diagram of the minimized expression. X= A’B’C’D+ A’B’C’D+A’BC’D

A gun barrel mass 560 kg is designed with the following data: Initial recoil velocity 36 m/sec;

Recoil distance on firing 1.5 m, calculate: (a) spring constant, (b) damping coefficient, and (c) time

required for the barrel to return to a position 0.12 m from its initial position.

Unit mass of a certain fluid is contained in a cylinder at an initial pressure of 25 bar. The fluid is p * V ^ 2 = allowed to expand reversibly behind a piston according to a law constant until the volume is doubled. The fluid is then cooled reversibly at constant pressure until the piston regains its original position; heat is then supplied reversibly with the piston firmly locked in position until the pressure rises to the original value of 25 bar. Calculate the net work done by the fluid, for an initial volume of 0.05 m^ 3 .

A resistive coil draws 2A at 110 V after operating for a long time. If the temperature rise is 55°C above the ambient temperature of 20°C, calculate the external resistance which must be initially connected in series with the coil to limit the current to 2A. The temperature coefficient of the material of the coil is 0.0043 per °C at 20°C.