when you analyze a problem, you first separate what is known from what is unknown
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Chapter 4: Problem Solving. When you analyze a problem, you first separate what is known from what is unknown. Then you decide on a strategy that uses the known data to solve for the unknown. After you solve a problem, you need to evaluate your answer to decide if it makes sense. - PowerPoint PPT PresentationTRANSCRIPT
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• When you analyze a problem, you first separate what is known from what is unknown.
• Then you decide on a strategy that uses the known data to solve for the unknown.
• After you solve a problem, you need to evaluate your answer to decide if it makes sense.
Chapter 4: Problem Solving
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A Problem Solving Strategy
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A Problem Solving Strategy
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A Problem Solving Strategy
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A Problem Solving Strategy
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Dimensional Analysis
• Dimensional analysis is a method of problem-solving that focuses on the units used to describe matter.
• For example, if you want to convert a temperature in degrees Celsius to a temperature in kelvins, you focus on the relationship between the units in the two temperature scales.
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Dimensional Analysis• A conversion factor is a ratio of equivalent
values used to express the same quantity in different units.
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Dimensional Analysis
• A conversion factor is always equal to 1.
• Because a quantity does not change when it is multiplied or divided by 1, conversion factors change the units of a quantity without changing its value.
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Dimensional Analysis
• Dimensional analysis often uses conversion factors.
• Suppose you want to know how many meters are in 48 km.
• You need a conversion factor that relates kilometers to meters.
• You know that 1 km is equal to 1000 m.
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Dimensional Analysis
• Because you are going to multiply 48 km by the conversion factor, you want to set up the conversion factor so the kilometer units will cancel out.
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Using Multiple Conversion Factors
• It is common in scientific problems to use dimensional analysis to convert more than one unit at a time.
• For example, what is a speed of 550 meters per second in kilometers per minute?
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Using Multiple Conversion Factors
• First convert meters to kilometers. Set up the conversion factor so that the meter units will cancel out.
• Next convert seconds to minutes. Set up the conversion factor so that the seconds cancel out.
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Your friend is 1.56 m tall. How many millimeters tall is your friend?
1560 mm
Question 1
Answer
Assessment QuestionsAssessment Questions
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How many hours are there in one week? How many minutes are there in one week?
168 h; 10 080 min.
Question 2
Answer
Assessment QuestionsAssessment Questions