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Estimation of physical quantities
Estimation supports problem solving where exact data are unavailable.
0
Objectives
10
Flashcards
10
Questions
90 min
Study time
AqaA LevelPhysicsMeasurements and their errors
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Orders of magnitude and sensible estimates4 objectives
- Make sensible order-of-magnitude estimates for physical quantities.
- State assumptions used in estimation problems.
- Use approximate values to check whether a calculated answer is realistic.
- Compare estimated and calculated values using appropriate reasoning.
Key terms
Order of MagnitudeSensible EstimateApproximate ValueAssumption in Estimationestimated valuecalculated valuecomparison reasoning
Exam tips
- Estimate the Height of a Building: To estimate the height of a building, use the rule of thumb that a typical floor height is about 3 meters. Count the number of floors and multiply by 3.
- Estimate the Mass of a Common Object: Estimate by comparing with a familiar object or scale, then state the assumption that makes the estimate reasonable.
Common mistakes
- Misunderstanding Order of Magnitude: To fix this, remember that an order of magnitude estimate is a rough approximation that simplifies the value to the nearest power of ten. For example, instead of estimating the mass of an object as 150 kg, round it to 100 kg (10^2) or 1000 kg (10^3) depending on the context.
- Ignoring Assumptions in Estimation: To correct this, clearly state any assumptions you are making when estimating a physical quantity. For instance, if estimating the height of a building, assume an average floor height of 3 meters per floor to guide your calculations.
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