principles of engineering - nashua school districtnashua.edu/paradisem1/poe/practice final...

Project Lead The Way® Copyright 2006 - of 10

Principles of Engineering Final Examination

Part B High School Credit Performance

Fall 2006-07

Student Name: ___________________________________ Date: _____________________ Class Period: _____________

Total Points: ____________/36 Converted Score: ____________/50


Directions: Complete all of the items in problems 1 through 8. To receive full credit on any problem that requires calculations, you must: 1) identify the formula, 2) show substitutions, and 3) state the answer with the correct units. Reference Formula Tables are provided on Pages 9 & 10.

1. Study the strut and cable in Figure 1 and its free body diagram in Figure 2

and complete the following problems.

a) Calculate the length of truss member BC. (answer precision = 0.00) [3 points]

b) Using the free body diagram in Figure 3, calculate the magnitude of the reaction force FBC which occurs at joint B. (answer precision = 0.00) [3 points]

Figure 3

Figure 1

A

C

B

Figure 2

2. A soccer ball is kicked from the ground with a velocity of 60 ft/s at an

angle of 40º degrees, and eventually lands at the same height, as shown in Figure 4. Use 32.15 ft/sec2 for acceleration due to gravity.

How far away does the ball land from the place it wprecision = 0.00) [3 Points]

3. The cylindrical bar, shown in Figure 5, has a cross-

sectional area of 7 in2 and is subjected to an axial load, as it is being pulled away from a wall with a fo of 200 lbs. Determine the stress in the bar. (answer precision = 0.00) [3 Points]
Figure 4

Figure 5

as kicked? (answer

rce


4. A tensile test specimen was tested under a tensile load. The force – displacement diagram that resulted is shown in Figure 6.

a) Study Figure 6 below. Write the letter from the diagram that matches each

term. [4 Points]

_____ Rupture _____ Yield Point _____ Proportional Limit _____ Ultimate Force

b) What kind of material would the specimen be if it had failed at point B? Circle the correct answer below. [1 Point]

Brittle material Ductile material

Figure 6

5. The closed-loop program shown below is designed to send a shuttle back and forth between two points. In one direction the lamp will be on. And in the other direction the lamp will be off. Study the program description and decide which of the program elements from the answer bank (A through G) must be used to complete the flowchart program. Write the letter of the correct icon in the corresponding empty box. No icon will be used more than once, and some may not be used at all. [4 points]

Program Description:

When the program starts, shuttle (M1) is turned ON in the clockwise direction, and the computer checks to see if limit switch I1 (wired normally open) is being pressed. The program will loop back until switch I1 is pressed. From there, shuttle M1 will stop and then start again in the counter-clockwise direction while turning on lamp M2. The computer will then loop back until switch I2 (wired normally open) is pressed. Once I2 has been pressed, lamp M2 turns off and shuttle M1 stops. The program then loops back to the beginning.

CW


ON

OFF


6. The incomplete image below identifies a 9-step design process. You are to place the steps of the design process in the right order below. Five answers have been completed. [4 points]

____ Define the Criteria ____ Model and Prototype ____ Test and Evaluate ____ Choose a Solution ____ Identify the Need, Want or Problem ____ Redesign and Improve ____ Generate Alternative Solutions ____ Develop the Solution ____ Investigate and Research

1

7

9

2

3


7. Study the technical drawing below, and sketch the missing object lines and hidden lines. There are two missing lines in each of the orthographic views. [6 points]

8a. What class of lever is shown in

_________________________

_________________________

_________________________

_________________________

8b. How much resistance force is n

(answer precision = 0.0) [3 po

Figure 7


Figure 7? Justify your answer. [2 points] ___________________________________

___________________________________

___________________________________

___________________________________

eeded to balance the 18 lb. load? ints]


POE Exam Reference Tables

Circular Shapes Formulas Variables

C = circumference C = πD π = pi A = πr2 D = diameter

A = area r = radius

Electrical Systems Formulas Variables

E = voltage E = IR I = current

R = resistance

Mechanisms

Formulas Variables MA = Mechanical Advantage MA = R ÷ E R = resistance force Lever MA = LE ÷ LR E = effort force

Axle MA = LE ÷ LR LE = distance to effort = Total number of strands supporting

the load LR = distance to resistance

Inclined Plane or Wedge MA = L ÷ H L = slope length Screw MA = C ÷ SP H = slope height or width thickness SP = 1 ÷ TPI C = circumference SP = screw pitch TPI = threads per inch

Statics Static Equilibrium

Properties of Materials

Formulas Variables δ = total deformation

σ = P ÷ A σ = stress ∈ = δ ÷ L ∈ = strain

δ = PL ÷ AE E = modulus of elasticity, Young’s Modulus E = σ ÷ ∈ P = axial force

E = (P1-P2)L0 /( δ 1-δ2)A A = area

Formulas Variables

M = moment about a point

M = FD F = force

D = perpendicular distance

Formulas Variables S = sum

SFX=0=X(right) – X(left) F = force

SFY=0=Y(up) – Y(down) M = moment about a point

SM=0=CCW - CW CCW = counter-clockwise

CW = Clockwise


Gear Ratios Formulas Variables

GR = gear ratio N in = number of teeth on driver gear

N out = number of teeth on driven gear GR = Input Rate / Output Rate D in = driver gear diameter, in SR = Win / Wout D out = driven gear diameter, in Win / Wout = Dout / Din W in = driver gear speed, rpm Tin / Tout = Din / Dout W out = driven gear speed, rpm

T in = torque of driver gear, ft lbs. T out = torque of driven gear, ft lbs. SR = speed ratio

Kinematics

Formulas Variables sin θ= opposite / hypotenuse θ = angle cos θ= adjacent / hypotenuse tan θ= opposite / adjacent

Formulas Variables vi = initial velocity θ = angle g = gravity

Vi2 sin2θ

x= g

x = range

Right Triangle Ratios

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