Engineering Answers

State and prove final value theorem in laplace transform.

1. A pipe 0.093 m² in area, carries a discharge of 0.283 m² / s of water. If it enlarges suddenly to 0.372 m² and if the pressure in the smaller section is 4.8 kN / m², find (a) the head lost, (b) the pressure in the larger part, (c) the power needed to force the water through the enlargement.

2.Water is siphoned out of a reservoir using a bent pipe (DEF) that is 24 m long and 25 mm in diameter. The end D is below the water surface and 150 mm above the base of the reservoir. The length DE is vertical and 9 m long and EF is 15 m long and the free end F is 1.5 m below the base of the reservoir. Assuming a barometric pressure of 10.3 m of water and that siphon action at E ceases when the absolute pressure is 1.8 m of water, determine the limiting velocity of water in the pipe and the depth of water in the tank when siphon action ceases. Assume that the loss of head in friction per metre is 0.5 v² / 2g where v = velocity in the pipe. 

1. A piston of 46 mm diam moves concentrically in a cylinder of 50 mm diam. The cylinder is filled with water and when the piston moves into the cylinder the water flows through the gap surrounding the piston. If the velocity of the piston is 75 mm/s relative to the cylinder, what is the velocity of the flow through the gap.

2. A 100 mm diam pipe carrying 1.8 m² / min of water suddenly enlarges to 150 mm diam. Find (a) the loss of head due to the sudden enlargement, (b) the difference in pressure in kN / m² in the two pipes taken between points just outside the area of disturbance due to change of section. The axis of the pipe is horizontal.

3.Water flows down a straight inclined pipe. At a point A, 45 m above datum, the section of the pipe suddenly doubles in area. The pressure in the smaller pipe at A is 860 kN / m² and the velocity of flow in the larger pipe is 2.4 m / s. Find the pressure in kN / m² at a point B which is 2.5 m above datum.

With increasing emphasis on energy conservation, there is an obvious move to construct buildings using methods and materials that do not absorb much heat from external sources. Discuss some of the developments in this field and the new ways/materials being employed for this purpose.

The voltage across a 1.1-kW toaster that produces a current of 5 A is

Write the equilibrium expression for the reaction of zinc and HCl. 

Should the equilibrium expression change if the size of the Magnesium pieces changes? Why or why not?

Should the reaction rate change if the size of the Zn pieces changes? Why or why not?

When the concentration of HCl is increased, what happens to the reaction rate? Is this what you expected? Why or why not?

Write the balanced equation for H2O2 decomposition in the presence of MnO2. The products are water and oxygen gas.