Thinking Like an Engineer
An Active Learning Approach 2e
Stephan, Bowman, Park, Sill, Ohland Copyright © 2013 Pearson Prentice-Hall, Inc.
Graphical Solutions
Modified by Prof. M. H. Imam
Graphical SolutionsThinking Like an Engineer 2e
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Thinking Like an Engineer
An Active Learning Approach 2e
Stephan, Bowman, Park, Sill, Ohland Copyright © 2013 Pearson Prentice-Hall, Inc.
Graph Interpretation
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Example Graphs_5
• Assume a 25 watt light bulb is turned on and then turned off 15 seconds later.
• Determine total energy
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Example Graphs_6
• Determine the total energy.
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Example Graphs_7
• A 25 watt light bulb is turned on for 15 seconds.
• The total energy absorbed by the light bulb at any given time is shown.
Graphical SolutionsThinking Like an Engineer 2e
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Thinking Like an Engineer
An Active Learning Approach 2e
Stephan, Bowman, Park, Sill, Ohland Copyright © 2013 Pearson Prentice-Hall, Inc.
Meaning of Line Shapes
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The Shape of a Line has Meaning
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The Shape of a Line has Meaning
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Example Graphs_8
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A. Increasing at a constant rate B. Equal a constant, positive value C. Equal zero
D. Equal a constant, negative value
E. Decreasing at a constant rate
F. Increasing at a constant rate
G. Increasing at a decreasing rate
H. Increasing at an increasing rate
I. Decreasing at a decreasing rate
J. Decreasing at an increasing rate
Thinking Like an Engineer
An Active Learning Approach 2e
Stephan, Bowman, Park, Sill, Ohland Copyright © 2013 Pearson Prentice-Hall, Inc.
Graphical Solutions
Graphical SolutionsThinking Like an Engineer 2e
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Breakeven Analysis
• Graphically analyze the costs of producing a product and the revenue from selling that product to assess profitability.
• Important terms:
• Cost: money must invest to make product
• Fixed cost: Equipment, Building
• Variable cost: Labor, Energy, Material
• Revenue: money make selling product
• Selling price
• Loss or Profit: difference between cost and revenue
• Breakeven Point: where Cost = Revenue
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Breakeven Analysis
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Selling Price Variable Cost
Breakeven Point
Example Graphs_9a
1. How many Fire Ant Destroyers must the company produce and sell to break even? Answer to the nearest 10,000 (the last four digits as zero).
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Thinking Like an Engineer 2e
170,000 units
Example Graphs_9b
2. How many Fire Ant Destroyers must the company produce and sell to make a profit of $500,000? Answer to the nearest 10,000 (the last four digits as zero).
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260,000 units
Example Graphs_9c 3. What is the sales price of one Fire Ant Destroyer?
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$10 / unit
Selling Price =
Slope of Revenue Line
Example Graphs_9d
4. If the sales price of one Fire Ant Destroyer was increased by $1, how many units must the company produce and sell to break even?
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140,000 units
Example Graphs_9e
4. If the sales price of one Fire Ant Destroyer was decreased by $1, how many units must the company produce and sell to break even?
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210,000 units
