Civil and Environmental Engineering Answers

A piece of equipment that was purchased 2 years ago by Toshiba Imaging for $50,000 was expected to have a useful life of 5 years with a $5000 salvage value. Its performance was less than expected, and it was upgraded for $20,000 one year ago. Increased demand now requires that the equipment be upgraded again for another $17,000 so that it can be used for 3 more years. If upgraded, its annual operating cost will be $27,000 and it will have a $12,000 salvage after 3 years. Alternatively, it can be replaced with new equipment priced at $65,000 with operating costs of $14,000 per year and a salvage value of $23,000 after 6 years. If replaced now, the existing equipment will be sold for $7000. Determine the values of P, S , AOC, and n for the defender in a replacement study. 

A concrete pipe of diameter 1 000 mm is laid at a slope of 1 in 100. Estimate the rate at which the water will run down the pipe so that it remains uniformly half full. Use C = 49 SI Units.

An asset that was purchased 3 years ago for $100,000 is becoming obsolete faster than expected. The company thought the asset would last 5 years and that its book value would decrease by $20,000 each year and, therefore, be worthless at the end of year 5. In considering a more versatile, more reliable high-tech replacement, the company discovered that the presently owned asset has a market value of only $15,000. If the replacement is purchased immediately at a first cost of $75,000 and if it will have a lower annual worth, what is the amount of the sunk cost? Assume the company’s MARR is 15% per year.  

A sand and gravel pit purchased for $900,000 is expected to yield 50,000 tons of gravel and 80,000 tons of sand per year. The gravel will sell for $6 per ton and the sand for $9 per ton. (a) Determine the depletion charge according to the percentage depletion method. The percentage depletion rate for sand and gravel is 5%. (b) If taxable income is $100,000 for the year, is this depletion charge allowed? If not, how much is allowed?  

A company just purchased an intelligent robot, which has a first cost of $80,000. Since the robot is unique in its capabilities, the company expects to be able to sell it in 4 years for $95,000. (a) If the company spends $10,000 per year in maintenance and operation of the robot, what will the company’s MACRS depreciation charge be in year 2? Assume the recovery period for robots is 5 years and the company’s MARR is 16% per year when the inflation rate is 9% per year. (b) Determine the book value of the robot at the end of year 2.  

A 1 M solution of Cu(NO3)2 is placed in a beaker with a strip of Cu metal. A 1 M solution of SnSO4 is placed in

a second beaker with a strip of Sn metal. A salt bridge connects the two beakers, and wires to a voltmeter link the

two metal electrodes.

(a) Which electrode serves as the anode and which as the cathode?

(b) Which electrode gains mass and which loses mass as the cell reaction proceeds?

(c) Write the equation for the overall cell reaction.

(d) What is the emf generated by the cell under standard conditions?

A 500mm diameter pipeline discharges water from a large reservoir. Determine the maximum possible elevation of its summit at B for a discharge of 2. 15m3/s without the absolute pressure becoming less than 20 KN/m2. Take atmospheric pressure as 10^6

Archaeologists used pieces of burned wood, or charcoal, found at the site to date

prehistoric paintings and drawings on walls and ceilings of a cave in Lascaux, France. See Figure 3.1.8. Use the information on page 84 to determine the approximate age of

a piece of burned wood, if it was found that 85.5% of the C-14 found in living trees of

the same type had decayed.

 Water flows at a depth of 40 cm in a100-cm-diameter storm sewer. Calculate the flow rate and the mass flux if the average velocity is 3m/s.

A symmetrical parabolic curve has a descending grade of -0.80% which meets an ascending grade of +0.40% at sta

10+020 having an elevation of 240.62 m. The maximum allowable change of grade per 20-m station is 0.15%

1. Determine the length of the parabolic curve.

2. Determine the stationing of the lowest point on the curve

3. Determine the elevation of the lowest point on the curve.