Questions and Answers of Exploring Engineering Introduction

How many kmol are contained in 3.0 kg of ammonia, NH3? (A: 0.18 kmols)
Your course instructor claims that energy is not really conserved. He or she uses the example of a spring that is compressed and then tied with a nylon string. When the compressed spring is put into
After working for a company for several years, you feel you have discovered a more efficient energy conversion method that would save your company millions of dollars annually. Since you made this
Review Exercises 14 through 17 in Chapter 3 concerning the dynamics (and consequent fate) of bungee jumpers. Draw a control surface around the jumper and cord. Show the various forms of energy
In order to maintain a speed v on a horizontal road a car must supply enough power to overcome air resistance. That required power goes up with increasing speed according to the formula:P = Power in
Determine the amount of gasoline consumed per second by the automobile in Example 4.9 if it was travelling at 41. m/s. (Assume power required increases as the cube of speed)Example 4.9If gasoline
Suppose the car in Exercises 23 and 24 has stored 1.00 × 102 megajoules (MJ) of energy in its battery. Suppose the electric propulsion system of the car can convert 90. percent of that energy into
Suppose the car in Exercise 23 has a mass of 1000. kg and is traveling at 33.5 miles per hour. As it comes to a stop, the regenerative braking system operates with 75% efficiency. How much energy per
A hybrid car is an automobile that achieves high fuel efficiency by using a combination of thermal energy and electrical energy for propulsion. One of the ways it achieves high fuel efficiency is by
Suppose the world originally had 10 trillion (10.0 x 1012) barrels of oil. Use the data of exercise 25 to predict again when the oil will start to run out.Exercise 25Suppose the world originally had
A truck starter motor must deliver 15 kW of power for a brief period. If the voltage of the motor is 12 V, what is the current through the starter motor while it is delivering that level of power?
An electric oven is heated by a circuit that consists of a heating element connected to a voltage source. The voltage source supplies a voltage of 110. V, which appears as a voltage drop across the
What would be the current in the lightbulb in Example 4.6 if it sustained a voltage drop of 120. V and required a power of 100. W?Example 4.6A battery sustains a voltage drop of 3.0 V across a small
What would be the power required by the lightbulb in Example 4.6 if it sustained a voltage drop of 120. V?Example 4.6A battery sustains a voltage drop of 3.0 V across a small lightbulb and produces a
A stiff 10.0 g ball is held directly above and in contact with a 600.0 g basketball and both are dropped from a height of 1.00 m. What is the maximum theoretical height to which the small ball can
Suppose a spaceship is designed to withstand a micrometeoroid impact delivering a TKE of a million joules. Suppose that the most massive micrometeoroid it is likely to encounter in space has a mass
Micrometeoroids could strike the International Space Station with impact velocities of 19 km/s. What is the translational kinetic energy of a 1.0 gram micrometeoroid traveling at that speed? (A: 1.8
Solve Exercise 14 in Engineering English units. (Check your answer by converting the answer to Exercise 14 into Engineering English units.)Exercise 14A hypervelocity launcher is an electromagnetic
A hypervelocity launcher is an electromagnetic gun capable of shooting a projectile at very high speed. A Sandia National Laboratory hypervelocity launcher shoots a 1.5 gram projectile that attains a
Aeronautical engineers have invented a device that achieves the conversion of kinetic to potential energy as described in Exercise 12. The device achieves this conversion with high efficiency. In
A vehicle of mass 1.50 × 104 kg is traveling on the ground with a TKE of 4.69 × 108 J. By means of a device that interacts with the surrounding air, it is able to convert 50.% of the TKE into GPE.
Suppose the 1.00 kg book in Example 4.8 fell from a height of 2.50 meters. What would be the final energy of the classroom after the exchange of thermal energy?Example 4.8 Control Boundary Heat
Determine the amount of gasoline required in Example 4.7 if the automobile was traveling at 55. miles per hour.Example 4.7A gallon of gasoline can provide about 1.30 × 105 kJ of chemical energy.
An airplane with a mass of 1.50 × 104 kg is flying at a height of 1.35 × 103 m at a speed of 250.0 m/s. Which is larger—its translational kinetic energy or its gravitational potential energy with
Chunks of Earth orbital debris can have speeds of 2.3 × 104 miles per hour. Determine the translational kinetic energy (TKE) of a 2.0 × 103 lbm chunk of this material in SI units. (A: 4.8 × 1010 J
A spring at ground level—that is, at height = 0.00 m—shoots a 0.80 kg ball upward with an initial kinetic energy of 245 J. Assuming that all the initial TKE is converted to GPE, how high will the
Determine the gravitational potential energy (GPE) of an 8.00 × 103 kg truck 30. m above the ground. (A: 2.4 × 106 J to two significant figures, since h is known only to two significant figures)
What would be the gravitational potential in SI units of the anvil in Example 4.5 if its mass was 100. kg and the cliff was 1000. meters high?Example 4.5Wile E. Coyote holds an anvil of mass 100. lbm
Repeat the calculation of Example 4.2 in Engineering English units. Check that your answers agree with the solution in Example 4.2 using the appropriate conversion factors.Example 4.2Estimate the
Determine the translational kinetic energy of the atmosphere in Example 4.2 if the average air velocity increased to 15. m/s.
Determine the translational kinetic energy in Engineering English units of the automobile in Example 4.1 if its mass was increased to 4.00 x 103 lbm.Example 4.1What is the translational kinetic
Determine the translational kinetic energy of the automobile in Example 4.1 if its speed was reduced to 55. miles per hour.Example 4.1What is the translational kinetic energy of an automobile with a
Stephanie knew Adam, the Environmental Manager, would not be pleased with her report on the chemical spill. The data clearly indicated that the spill was large enough that regulations required it to
You e-mail a classmate in this course for some information about a spreadsheet homework problem. In addition to answering your question, your classmate also attaches a spreadsheet solution to the
Your friend tells you that the need–know–how–solve problem-solving method seems overly complicated. He or she just wants to find the answer to the problem in the quickest possible way—say, by
Repeat exercise 26, but instead of assuming the exponential growth in consumption continuing unabated by a factor of 5 in every quarter-century since 1850, curtail growth since 2000. and assume
Suppose the world originally had three trillion (3. x 1012) barrels of oil and its exploration began in 1850. Suppose 10.0% of the remaining undiscovered oil has been found in every quarter century
An unnamed country has the following population of passenger cars on its roads as determined by 250 kg mass differences. You have to make these data clear to the undersecretary to that country’s
Name a product or group of products that does not fit the generalization you made in exercise 22 and add and label the point on the graph in exercise 21. To get a better perspective use a log scale
What (perhaps surprising) simple generalization about the cost of things might we make based on the table and graph of exercise 21? Does the comparative lack of spread in price surprise you?In
Suppose that the purchase price of automobiles varies with weight according to the formula that weight in lbf × $8.00, and gas mileage varies according to mpg = (84,500 mile-lbf/gal)/W – 3.0
For the objects listed in the previous exercise, make a table and graph of the cost of objects in dollars as a function of their weight in newtons. It is suggested for this graph to use a line (not
If we were to double the price of the automobile in exercise 18, what would its gas mileage have to be in order to cost the same to operate per mile as the automobile in exercise 18?The fixed costs
Estimate the operating cost per mile of an automobile with a price of $15,000 that gets 30.0 miles per gallon. (A: $0.32/mile)The fixed costs per year of operating an automobile is approximately 20.%
By copying and pasting your spreadsheet from exercise 15, find and plot the values of L needed (in ft) vs. W, weight of jumper (in lbf) for successful bungee jumps (coming to a stop 5.0 ft above the
If the height of the parapet is 200. ft, and the weight of the person is 150. lbf, and the unstretched length L = 45.0 ft, find a value of K that enables this person to stop exactly five feet above
Americans are getting heavier. What’s the jumper’s weight limit for a 40.0 ft unstretched bungee with stiffness of K = 6.25 lbf/ft? Graph final length L + x vs. W for weights from 100. lbf to
If the height of the cliff is 150.0 ft, K = 6.25 lbf/ft, L = 40.0 ft, and the person’s weight is 150.0 lbf, will the person be able to bungee jump safely? Support your answer by giving the final
Suppose the formula for weight of the gas was G = Wb, where b can be varied in the range 0.50–0.75. Graph the range of a 3.69 × 103 lbf car as a function of b.Suppose that the weight of the
What is the heaviest car that can achieve a range of 600. miles? (A: 3.69 × 103 lbf)Suppose that the weight of the gasoline in lbf in a car’s gas tank equaled the weight of the car in lbf to the
What is the fuel usage in miles per gallon of a 3.00 × 103 lbf car?Suppose that the weight of the gasoline in lbf in a car’s gas tank equaled the weight of the car in lbf to the 2/3 power (i.e.,
Using the technique introduced in Example 3.8, create a spreadsheet graph of the following data for the median annual salaries in dollars for engineers based on years of experience, supervisory
Using the renter mileage information given in the previous exercise and the miles per gallon information given in Example 3.5, determine the average gallons per journey segment and average per driver
Use the spreadsheet analysis in Example 3.4 to determine the total miles driven by each driver and the average miles driven in each category for the following car renters:Example 3.4 Renter City
Suppose the mass used in Example 3.3 was increased from 10.0 kg to 20.0 kg, and the wire stretched by twice as much. If the 20.0 kg mass was then used to stretch a 4.00 m piece of the same steel
Suppose you want to make a cylindrical can to hold 0.01 m3 of soup. The sheet steel for the can costs $0.01/m2. It costs $0.02/m to seal circular pieces to the top and bottom of the can and along the
Of all the rectangles that have an area of one square meter, what are the dimensions (length and width) of the one that has the smallest perimeter? Solve by graphing on a spreadsheet.
You are attending a student engineering organization regional conference along with five other students from your institution. The night before the group is scheduled to return to campus, one of the
A company purchased an expensive computer program for your summer job with them. The license agreement states that you can make a backup copy, but you can use the program on only one computer at a
The great physicist Enrico Fermi used to test the problem-solving ability of his students at the University of Chicago by giving them the following problem: How many piano tuners are there in the
Suppose the ranch in Example 3.1 was a rectangle with the long side twice as long as the short side. Using the same financial information ($32,000. available funds, $10,000. a mile for fence, and
Suppose the ranch in Example 3.1 was an equilateral triangle instead of a square. Using the same financial information ($32,000. available funds, $10,000. a mile for fence, and $100,000. per square
Suppose the ranch in Example 3.1 was a circle instead of a square. Using the same financial information ($32,000. available funds, $10,000. a mile for fence, and $100,000. per square mile land cost),
On December 11, 1998, the Mars Climate Orbiter was launched on a 760 million mile journey to the Red Planet. On September 23, 1999, a final rocket firing was to put the spacecraft into orbit, but it
You are browsing the Internet and find some units conversion software that may be useful in this course. You would like to download the software on your PC at school and use it in this course. What
Suppose you were going to design a front door and doorway to fit snugly enough to keep out the drafts, yet to be easy to open. (You are not showing off precision carpentry here, but merely designing
Round off to three significant places: 1.53, 15.345, 16.67, 102.04, - 124.7, and 0.00123456.Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three significant
A machinist has a sophisticated micrometer that can measure the diameter of a drill bit to 1/10,000 of an inch. What is the maximum number of significant figures that should be reported if the
Calculate with the correct significant figures:(a) 100/(2.0 × 102),(b) (1.0 × 102)/(2.0 × 102). (A: 0.5, 0.50) What is 2.68 × 108 minus 2.33 × 103 to the correct significant figures? (A: 2.68 ×
Calculate with the correct significant figures:(a) 10/6,(b) 10.0/6,(c) 10/6.0,(d) 10./6.0,(e) 10.0/6.00.Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three
Calculate with the correct significant figures:(a) 100/(2.0 × 102),(b) (1.0 × 102)/(2.0 × 102). (A: 0.5, 0.50)Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to
Suppose you were going to accelerate a 2000. kg car by the Rube Goldberg contraption shown in the following figure. The fan (A) blows apples (C) off the tree (B) into the funnel and thus into the bag
Suppose a planet exerted a gravitational force at its surface that was 0.6 the gravitational force exerted by Earth. What is gc on that planet?Assume that on the surface of the Earth, g = 9.81 m/s2 =
How many lbf does it take for a 4.0 × 103 lbm car to achieve 0 to 60 mph in 10. seconds? (A: 1.1 × 103 lbf)Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three
The force of gravity on the Moon is one-sixth (i.e., 1/6.0) as strong as the force of gravity on Earth. An apple weighs 1.0 N on Earth.(a) What is the mass of the apple on the Moon, in lbm?(b) What
A person pushes a crate on a frictionless surface with a force of 100. lbf. The crate accelerates at a rate of 3.0 feet per second2. What is the mass of the crate in lbm? (A: 1.07 × 103 lbm)Assume
A rocket sled exerts 3.00 × 104 N of thrust and has a mass of 2.00 × 103 kg. In how much time does it do “zero to sixty”? How many g’s (see Exercise 14) does it achieve?Assume that on the
If power (measured in W, or watts) is defined as work (measured in J, or joules) performed per unit time (measured in s), and work is defined as force (measured in N or newtons) × distance (measured
What is your mass in kilograms divided by your weight in pounds? Do you have to step onto a scale to answer this question? How did you answer the question?Assume that on the surface of the Earth, g =
Acceleration is sometimes measured in g’s, where 1.0 g = 9.8 m/s2. How many g’s correspond to the steady acceleration of a car doing “zero to sixty”15 in 10.0 seconds? (A: 0.27 g)Assume that
What is the value and units of gc in the Engineering English system on the Moon?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three significant figures). Make
What force would be necessary in Example 2.4 if the mass were 735 lbm?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three significant figures). Make sure you are
What would be the weight of the body in Example 2.3 on the Moon where the acceleration of gravity is just gMoon = 1.64 m/s2?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e.,
What would be the force on the body in Example 2.2 if its mass were 856 grams?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three significant figures). Make sure
What would the 5.00 slug mass in Example 2.1 weigh on the Moon where the acceleration of gravity is only 1/6 of that on Earth?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2
Suppose the mass in Example 2.1 was 50.0 slugs. What would be its weight in lbf (pounds force)?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three significant
If the pressure in the tire on your car is 32.0 lbf/in2 (or psi), what is its pressure in SI units?Assume that on the surface of the Earth, g = 9.81 m/s2 = 32.2 ft/s2 (i.e., each to three significant
There are 39 inches in a meter. What is the area in the SI system of the skin of a spherical orange that is 4.0 inches in diameter? (A: 3.3 × 10 -2 m2)Assume that on the surface of the Earth, g =
An acre originally was defined as the amount of land that an oxen team could plow in a day.14 Suppose a team could plow 0.4 hectare per day, where a hectare is 104 m2. There are 1609 meters in a
The height of horses from the ground to their shoulder is still measured in the old unit of hands. There are 16 hands in a fathom and 6.0 feet in a fathom. How many feet high is a horse that is 13
Identify whether you would perform the following unit conversions by definition, by conversion factors, by geometry, or by scientific law.a. How many square miles in a square kilometer?b. How many
If a US gallon13 has a volume of 0.134 ft3 and a human mouth has a volume of 0.900 in3, then how many mouthfuls of water are required to fill a 5.00 US gallon can? (A: 1.29 × 103 mouthfuls)Assume
Jan, a professional engineer on unpaid leave, is a part-time graduate student at a small private university and is enrolled in a research class for credit taught by Dimanro, a mechanical engineering
Derek Evans used to work for a small computer firm that specializes in developing software for management tasks. Derek was a primary contributor in designing an innovative software system for
Marvin Johnson is an Environmental Engineer for one of several local plants whose water discharges flow into a lake in a flourishing tourist area. Included in Marvin’s responsibilities is the
Some American companies have refused to promote women into positions of high authority in their international operations in Asia, the Middle East, and South America. Their rationale is that business
Paul Ledbetter is employed at Bluestone Ltd. as a manufacturing engineer. He regularly meets with vendors who offer to supply Bluestone with needed services and parts. Paul discovers that one of the
You are testing motorcycle helmets manufactured by a variety of your competitors. Your company has developed an inexpensive helmet with a liner that will withstand multiple impacts, but is less
It is the last semester of your senior year and you are anxious to get an exciting electrical engineering position in a major company. You accept a position from Company A early in the recruiting
Repeat Example 1.4 using the Five Cornerstones of Ethical Behavior. Solve using the Engineering Ethics Matrix.Example 1.4You are a civil engineer on a team designing a bridge for a state government.

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