August 14

FE Practice Exam 1 Part IV

Problem #31

What the standard units used when using the Reynolds Number?
A) ft/s2
B) centipoise
C) kg/s
D) None

Problem #32

What is the thermal efficiency for a Carnot engine that operates between 100F and 400K?
A) 75%
B) 77.5%
C) 7.8%
D) 22.3%

Problem #33

What is the natural frequency of a body that has a period of oscillation of 2.7 seconds?
A) 2.7 s
B) 0.75 s
C) 2.33 s
D) 4.65 s

Problem #34

What cycle is the most efficient?
A) Carnot
B) Brayton
C) Diesel
D) Otto

Problem #35

An iron sphere with a mass of 1.5 kg hangs from a 15 cm long spring. If the spring constant is 0.75 N/m what is the period of oscillation when the sphere is pulled down and released?
A) 3.2 s
B) 8.9 s
C) 4.4 s
D) 12.5 s

Problem #36

A plane intercepts the coordinate axis at (4,6,10). What are the Miller indices for this plane?
A) (2,3,5)
B) (15,10,6)
C) (-4,-6,-10)
D) (10,6,4)

Problem #37

A copper ball that is 1.5 m in diameter has a temperature of 100C. The environment is at 0C. If the emissivity of copper is 0.15 how much power is radiated by the copper ball?
A) 6 w
B) 5,264 W
C) 500 W
D) 1,164 W

Problem #38

What would the annuity be over a 20 year period that has an interest rate of 10% and a present worth of $500?
A) $58.75
B) $42.55
C) $8.51
D) $ 63.75

Problem #39

A group of dog pulls a sled across a snow covered surface. It takes 5 hours to pull the 200 kg sled 100 kilometers. If the static friction is 0.4 and the dynamic friction is 0.1 what is the average power exerted by the dog sled team?
A) 1,067 W
B) 5,333 W
C) 3,84 kW
D) 266.8 W

Problem #40

Reactions on average will proceed faster at a higher temperature because of which of the following?
A) There is less energy in the molecules
B) Molecules collide more frequently
C) The amount of exergy is diminished
D) The energy to start the reaction is higher

Questions

1 to 10
11 to 20
21 to 30

Answer Key

August 11

FE Practice Exam 1 Part III

Problem #21

What is happening to a substance when it is oxidized?
A) The substance is gaining electrons
B) The substance is losing electrons
C) The substance is giving off heat
D) The substance is absorbing heat

Problem #22

A 500 kilogram shipping container is raised from 300 meters. If the cable weight 5 kilograms per meter of length, what is the approximate work done?
A) 5,886 kN
B) 2,210 kN
C) 1,472 kN
D) 3,680 kN

Problem #23

What are the basic processes for an ideal, reversible Carnot cycle
A) Four isentropic
B) One isentropic, isobaric, isochoric, and isenthalpic
C) Two isothermal and two isentropic
D) Two adiabatic and two isobaric

Problem #24

Simplify the following expression

(9+3i)(6+8i)

A) 30 + 90i
B) 78 + 90i
C) 24i2 + 90i + 54
D) 54 + 90i

Problem #25

What is the percentage of CH4 on a mass basis if the volumetric analysis of the mixture is as follows

CH4     22%
CO2     45%
O2          5%
N2       14%

A) 68.7%
B) 5.6%
C) 12.2%
D) 13.6%

Problem #26

What is the largest load a 12 inch by 6 inch column can support if the normal stress can not exceed 65,000 PSI?
A) 130,000 lbs
B) 4,680,000 lbs
C) 32,500 lbs
D) 2,340,000 lbs

Problem #27

A 50 m3 vessel contains a mixture of 80% water and 10 m3 of water vapor. If the internal pressure of the vessel reads 100 kPa, what is the internal energy of the system?
A) 4,060,000 kJ
B) 4,000,000 kJ
C) 60,000 kJ
D) 3,940,000 kJ

Problem #28

A flange weighing 200 lbs is resting on a table. If the diameter of the flange is 10 inches what pressure does the flange exert on the table?
A) 17.7 kPa
B) 17.7 Pa
C) 2.56 kPa
D) 2.56 Pa

Problem #29

How many kilowatts are required to heat a flowing liquid that has a mass flow rate of 120 lbm/min with an entering enthalpy of 50 BTU/lbm and a leaving enthalpy of 10 BTU/oz?
A) 101.3 kW
B) 232.1 kW
C) 6,077 kW
D) 13,930 kW

Problem #30

You observe a 12 inch diameter by 0.5 in thick cylinder rolling along a horizontal surface. How many degrees of freedom does the cylinder have?
A) One
B) Two
C) Three
D) Four

Questions

1 to 10
11 to 20
31 to 40

Answer Key

August 8

FE Practice Exam 1 Part II

Problem #11

Which of the following statements is FALSE when concerning the hot working of metal?
A) Produce a fine grained product
B) Removes strain hardening
C) Combines of annealing and cold working
D) Decreases the density of the metal

Problem #12

What is the elongation of a 2 meter aluminum bar when it has been stressed to 512 MPa? (E = 69 GPa)?
A) 1.5 cm
B) 2.0 cm
C) 1.0 cm
D) 1.7 cm

Problem #13

Which of the following is FALSE with regards to creep
I. May involve the sliding of whole grains
II At high stresses creep is controlled by the movement of vacancies.
III Also known as hot flow
IV Creep is a time dependent deformation
A) I
B) II
C) III
D) IV

Problem #14

What is the oxidation state of Carbon in Carbonate (CO3-2)
A) -2
B) 4
C) 1
D) 2

Problem #15

A piston inside a cylinder undergoes an isentropic compression with the following values.
p_1= 4.57 \frac{N}{cm^2}

p_2= 34.07 \frac{N}{cm^2}

V_1 = 257 cm^3
If the specific heat ratio (k) is 1.4, What is the compressed volume?
A) 61.2  cm3
B)  30.5 cm3
C)  90.4 cm3
D)  257 cm3

Problem #16

What is the standard equation for calculating the future worth (F) when given the annual rate of return (I) and the present rate (P)?
A) F=P(1+i)^{n-1}
B) F=P(1+i)^n
C) F=P(1-i)^n
D) F=P(1+n)^I

Problem #17

A tube that is 10 feet long and 2 feet in diameter is placed in an air stream. The flow of the air is at a speed of 15 ft/s and is perpendicular to the long axis of the tube. If the coefficient of drag is 1.3 and the density of air is 0.075 lbm/ft3 What is the drag on the cylinder?
A) 150 lbf
B) 200 lbf
C) 320 lbf
D) 220 lbf

Problem #18

If a process is considered to be internally reversible and adiabatic, what can the change in entropy be assumed to be?
A) Entropy becomes Infinite
B) Entropy increases
C) Entropy decreases
D) Entropy does not change

Problem #19

What is the hydraulic diameter of a 20 inch diameter pipe that is half full?
A) 10 inches
B) 2.5 inches
C) 20 inches
D) 5 inches

Problem #20

You are tasked with identifying where the stress concentrations may appear on a support beam. Of the following locations which will not have a stress concentration?
I Near concentrated loads
II. Close to discontinuities of the beam
III Where distributed loads occur.
A) II & III
B) II
C) I & II
D) III

Questions

1 to 10
21 to 30
31 to 40

Answer Key

August 6

Fundamentals of Engineering (FE) Practice Exam 1

Problem #1

Which of the following are not an intensive property?

  1. Pressure
  2. Velocity
  3. Volume
  4. Density
  5. Kinetic Energy

A) I, II & III
B) IV & V
C) I, II & IV
D) III & V

Problem #2

Using the Gibbs Phase Rule, how many intensive properties are required to fix a mixture of water and ammonia that is in a liquid state?
A) 1
B) 2
C) 3
D) 4

Problem #3

How much heat is dissipated when a current of 15 amps passes through a 4 ohm resistor?
A) 3,075 btuh
B) 900 btuh
C) 2,700 btuh
D) 9,300 btuh

Problem #4

What is the gauge pressure of at a point that is 15 meters below the surface of water that has an atmospheric pressure of 14.7 PSIA?
A) 147,150 pa
B) 150,000 pa
C) 147,250 pa
D) 147,000 pa

Problem #5

A spaceship leaves the space station with an acceleration of 15 ft/s2. After 3 minutes the engines turn off and the acceleration is 0 ft/s2. What is the average velocity of the spaceship?
A) 81,100 ft/s
B) 1,350 ft/s
C) 243,000 ft/s
D) 2,700 ft/s

Problem #6

Which of the following can not be equal to 1 mol of the substance at standard conditions?
A) 20 grams of water
B) 6.02 x 1023 molecules of Uranium
C) 28 grams of N2
D) 22.4 liters on Argon

Problem #7

How much torque can be applied to a 6 inch outer diameter pipe that has a wall thickness of 0.25 inches when the maximum shear stress is 20,000 psi?
A) 23,400 in lbs
B) 250,000 in lbs
C) 37,400 in lbs
D) 30,000 in lbs

Problem #8

Your credit card has a nominal interest rate of 18%. If the interest is calculated monthly, what is the effective annual rate?
A) 19.0%
B) 18.5%
C) 19.6%
D) 20.1%

Problem #9

Find the slope of the line defined by:
y=2x^5 + 3x^4 + 2x^2 + 3x + 1
A) m = 2x^6 + 3x^4 + 2x^3 + 3
B) m = 10x + 12x^2 + 4x^4 + 3
C) m = 10x^5 + 12x^4 + 4x^2 + 3
D) m = 10x^4 + 12x^3 + 4x + 3

Problem #10

An 18 wheeler has a mass of 28,000 kilograms when fully loaded. The truck goes from 0 to 90 kilometers per hour in 120 seconds. What is the force on the 18 wheeler due to acceleration?
A) 1.08 kN
B) 15.82 kN
C) 10.71 kN
D) 5.83 kN

Questions

11 to 20
21 to 30
31 to 40

Answer Key

July 2

Exam Problem #28 (Thermal Efficiency)

Question

A steam turbine produces 1.21 gigawatts of electricity. The load on the cooling system is measured to be 520,000 tons. For this power generation system what is the thermal efficiency?
A) 55%
B) 43%
C) 30%
D) 34%

Answer

Today’s fundamental of engineering sample problem looks at calculating the thermal efficiency when given units in the metric and English systems

Equation

Thermal Efficiency

\eta = \frac {Q_{in} - Q_{out}}{Q_{in}}

Variables

Qin = 520,000 tons
Qout 1.21 gigawatts (gw)

Solution

First step is to convert the units to the same type. Since there are only two variables you can use either metric and convert the problem into watts or English and convert everything into tons. In this problem we are going to convert the units of watts into tons (1 ton = 12,000 btuh)

(\frac {1\ ton}{12,000\ btu})(\frac {3412\ btu}{1\ kilowatt}) = 0.283 \frac {ton}{kw}

Now to put everything back into the thermal efficiency equation

\eta = \frac {520,000 - (1,210\ mw)(1,000\ kw/mw)(0.283\ ton/kw)}{520,000} = 0.3415

 

The correct answer is D with a thermal efficiency of 34%