Chapter 1: Introduction Physics

Opening Activity: Write on the board any unit of measurement. Standards of Measurement

 There are many different systems of measurement.  A standard is needed to be able to effectively share results of one experiment to anyone  This class will use the SI (Systeme International) system of measurement *Fun Fact: USA invented the SI system and are one of only three countries that don’t use it. (Liberia and Myanmar being the other two.) Standards of Measurement

 The standard unit of measurement is the meter  In 1799 the meter was defined as the one millionth the distance from the equator to the North Pole  In Until 1960s the official “meter” was the distance between two lines on a piece of platinum-iridium alloy  It is now defined as the distance light travels in 3.333e-9 seconds Length

 The standard unit for Mass is Kilogram  Defined as the mass of a specific platinum iridium alloy cylinder kept at the International Bureau of Weights and Measures at Sevres, France.  Mass is defined as the resistance to acceleration of an object introduced to a force *Important Note: The SI unit for mass is NOT grams. ** Important Note: An objects mass is NOT its weight. Mass

 The standard unit for time is the second.  Based on the frequency of light radiating from a cesium- 133 atom  One second = radiations Time

 Some values of large objects or time spans are approximated (Radius of earth, Age of Universe)  These estimations are located on page 3 as well as the front and back covers of your text Approximate Values

 Matter is made up of atoms  Atoms are made up of a nucleus and an electron cloud surrounding said nucleus  Each different element has a differing number of protons in said nucleus (along with neutrons)  The electrons, neutrons and protons are made up of 6 particles called Quarks  The variation of elements compose different types of matter and the amount of atoms directly affects an objects mass Building Blocks of Matter

 Technique used in order to approximate or to check a equation based on the units of the individual quantities  Dimensions of equal magnitude can be combined as if they were algebraic quantities *Note that this technique should be used to check as it is not able to completely create an equation due to constants Dimensional Analysis

 Convert all properties into the three basic classifications of measurement  Length (L)  Time (T)  Mass (M)  After performing all algebra convert the classifications to SI units Steps

SI Units for Area, etc

Example

 Significant Figures: A reliably known digit  When multiplying two number the significant figures in the quotient is the same as the number with the fewer significant figures.  When adding two numbers the sum with have the same number of decimal places as the number with the fewest decimal places. *Note that rounding can cause a difference in the last sig fig between your answer and that in the back of the book Uncertainty in Measurement

 Several Carpet Installers make measurements for carpet installation in the different rooms of a restaurant. Compute the areas for the banquet hall, the meeting room and the dining hall taking into account sig figs. What total area of carpet is required for these rooms? Example Length (m)Width (m) Banquet Hall Meeting Room Dining Room13.89

 When using an equation all quantities must be converted into SI units.  This includes both internally in the metric system as well as from one system of measurement to another. 1mile = 1609 m1ft = m 1m = 39.37in 1in = 2.54 cm Conversion of Units

Process

 Convert using multiple conversion factors:  If a car is traveling at a speed of 28.0 m/s is the driver exceeding the speed limit of 55.0 mi/h? Example

 Sometimes knowing an exact number for something is impossible  It is alright in these situations to estimate to a factor of 10 that is close. Order of Magnitude

 How many dollar bills would it take to reach the moon stacked one on top of another?  Estimations say that 10 bills would be approximately one mm.  The distance to the moon is 4e5km away from the earth. Example

 Two types of coordinate systems  Cartesian (x,y)  Polar (r, θ) Graphing

 Read the problem  Draw a diagram  Label all physical quantities  Identify the values and list them in a chart  Choose your Equation(s).  Solve the equations for the unknowns  Substitute in known values  Check the answer if time allows *all odd numbered problems are answered in the book Problem Solving Strategy