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Name ___________________ Date _________ Block ___ GAC Physics Topic 1: Physics and physical measurement 1.1 The realm of physics Range of magnitudes of quantities in our universe 1.1.1 1.1.2 1.1.3 Assessment statement State and compare quantities to the nearest order of magnitude. State the ranges of magnitude of distances, masses and times that occur in the universe, from smallest to greatest. State ratios of quantities as differences of orders of magnitude. Estimate approximate values of everyday quantities to one or two significant figures and/or to the nearest order of magnitude. 1.2 Measurement and uncertainties The SI system of fundamental and derived units Assessment statement 1.2.1 State the fundamental units in the SI system. 1.2.2 Distinguish between fundamental and derived units and give examples of derived units. 1.2.4 State units in the accepted SI format. Teacher’s notes Distances: from 10–15 m to 10+25 m (sub-nuclear particles to extent of the visible universe). Masses: from 10–30 kg to 10+50 kg (electron to mass of the universe). Times: from 10–23 s to 10+18 s (passage of light across a nucleus to the age of the universe). For example, the ratio of the diameter of the hydrogen atom to its nucleus is about 105, or a difference of five orders of magnitude. 1.1.4 1.2.5 State values in scientific notation and in multiples of units with appropriate prefixes. Teacher’s notes Students need to know the following: kilogram, metre, second, ampere, mole and kelvin. Students should use m s–2 not m/s2 and m s–1 not m/s. For example, use nanoseconds or gigajoules. Uncertainty and error in measurement Assessment statement Teacher’s notes 1.2.6 Describe and give examples of random and systematic errors. 1.2.7 Distinguish between A measurement may have great precision yet may be precision and accuracy. inaccurate (for example, if the instrument has a zero offset error). 1.2.8 Explain how the effects of Students should be aware that systematic errors are not random errors may be reduced by repeating readings. reduced. 1.2.9 Calculate quantities and The number of significant figures should reflect the precision results of calculations to the of the value or of the input data to a calculation. Only a appropriate number of simple rule is required: for multiplication and division, the significant figures. number of significant digits in a result should not exceed that of the least precise value upon which it depends. The number of significant figures in any answer should reflect the number of significant figures in the given data. Uncertainties in calculated results Assessment statement 1.2.10 State uncertainties as absolute, fractional and percentage uncertainties. 1.2.11 Determine the uncertainties in results. Teacher’s notes A simple approximate method rather than root mean squared calculations is sufficient to determine maximum uncertainties. For functions such as addition and subtraction, absolute uncertainties may be added. For multiplication, division and powers, percentage uncertainties may be added. For other functions (for example, trigonometric functions), the mean, highest and lowest possible answers may be calculated to obtain the uncertainty range. If one uncertainty is much larger than others, the approximate uncertainty in the calculated result may be taken as due to that quantity alone. 1.3 Vectors and scalars Assessment statement 1.3.1 Distinguish between vector and scalar quantities, and give examples of each. 1.3.2 Determine the sum or difference of two vectors by a graphical method. 1.3.3 Resolve vectors into perpendicular components along chosen axes. Teacher’s notes A vector is represented in print by a bold italicized symbol, for example, F. Multiplication and division of vectors by scalars is also required. For example, resolving parallel and perpendicular to an inclined plane.