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General Physics 1  General Physics 1 Units, Physical Quantities, and Vectors Daily Objective: To solve measurement problems involving conversion of units, expression of measurements in scientific notation  PHYSICS A branch of Science explaining all of the phe...

General Physics 1  General Physics 1 Units, Physical Quantities, and Vectors Daily Objective: To solve measurement problems involving conversion of units, expression of measurements in scientific notation  PHYSICS A branch of Science explaining all of the phenomena in the universe to explain the nature of things around us.  PHYSICS It is considered as the foundation of all Sciences. PHYSICS  PHYSICS It is an experimental science. table Contributions of Physics to the World Understanding of Light, Matter, and Physical Processes table Contributions of Physics to the World Quantum Mechanics and Technological Innovations General Physics I Everyone is capable of learning Physics.  General Physics I Tips: 1. Understand your own learning style. 2. Make time to study. 3. Practice solving problems  General Physics I Tips: 1. Understand your own learning style. 2. Make time to study. 3. Practice solving problems UNITS OF MEASUREMENT Physical Quantity Any number that is used to describe a physical phenomenon quantitatively. Physical Quantity nternational System (SI Units) To make sure that scientists from different parts of the world understand the same thing when referring to a measurement, standards have been defined for measurements of length, time, and mass.  Length In 1960, atomic standard for meter was established using the wavelength of the orange-red light emitted by excited atoms of krypton 186Kr2  Length 1 meter is defined as the distance travelled by light in a vacuum in 1/299,792,458 second. Based on the definition that the speed of light is exactly 299,792,458 m/s.  Time The unit of time was defined as a certain fraction of the mean solar day, the average time between successive arrivals of the sun at its highest point in the sky.  Time 1 second is defined as 9,192,631,770 cycles of the microwave radiation due to the transition between the two lowest energy states of the cesium atom.  Mass Defined to be the mass of a metal cylinder kept at the International Bureau of Weights and Measures in France.  Mass 1 kg is defined to be the mass of a cylinder of platinum-iridium alloy at the International Bureau of weights and measures. Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units  Example 1 The world land speed record of 763.0 mi/h was set on October 15,1997, by Andy Green in the jet-engine car Thrust SSC. Express this speed in meters per second  Example 2 One of the world’s largest cut diamonds is the First Star of Africa (mounted in the British Royal Sceptre and kept in the Tower of London). Its volume is 1.84 cubic inches. What is its volume in cubic centimeters? In cubic meters?  Example 2 One of the world’s largest cut diamonds is the First Star of Africa (mounted in the British Royal Sceptre and kept in the Tower of London). Its volume is 1.84 cubic inches. What is its volume in cubic centimeters? In cubic meters?  Example 3 Convert 147 ft/s to miles/hr. Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units Conversion of Units PREFIX QUIZ 1. What is the base unit for length in metric system? 2. In metric system the prefix nano- means 3. What is the conversion factor to change kilograms to pounds? 4. What is the mass of 20.0 mL solution if its density is 1.84 g/mL? 5. 65.0ºC = ______ F Prefix Symbol Magnitude Giga- G 10^9 7. M 8. Kilo- k 9. Hecto- 10. 10^2 11. Da 12. Deci- 13. 14. Centi- C 15. Prefix Symbol Magnitude Giga- 6. 10^9 7. M 8. Kilo- k 9. Hecto- 10. 10^2 11. Da 12. Deci- 13. 14. Centi- C 15. Conversion of Units Why do we need to convert units? Conversion of Units How many inches are there in 3 meters? Conversion of Units How much time would it take for light to travel 10,000 feet?  General Physics 1 Uncertainty and Significant Figures  Measurem ent NOTE: Always has uncertainties. Uncertaint y Smallest Division: 1 mm= 0.1cm Uncertaint y 𝒔𝒎𝒂𝒍𝒍𝒆𝒔𝒕 𝒅𝒊𝒗𝒊𝒔𝒊𝒐𝒏 𝑼𝒏𝒄𝒆𝒓𝒕𝒂𝒊𝒏𝒕𝒚 = 𝟏𝟎 Uncertaint y Uncertaint y 𝟐.𝟓? 𝟐.𝟔? 𝟐.𝟔𝟏? Uncertaint y Uncertaint y  Uncertaint y What is the degree of uncertainty given the measurement?  Uncertaint y What is the degree of uncertainty given the measurement?  Uncertaint y What is the degree of uncertainty given the measurement?  Uncertaint y What is the degree of uncertainty given the measurement?  Percent Uncertainty  Percent Uncertainty  Uncertaint y What is the percent uncertainty given the measurement? Accuracy vs Precision  Accuracy Refers to how close a measurement is to the true value.  Precision Refers to how close the repeated measurements are to each other. Accuracy vs Precision Rounding off numbers Why do we need to round off numbers? Rounding off numbers Rules: 1. Numbers 1-4, round down! 2. Numbers 5-9, round up!  Significant Figures The number of digits in a value, often a measurement, that contribute to the degree of accuracy of the value.  Significant Figure Rules 1. All nonzero digits are significant.  Significant Figure Rules 1. All nonzero digits are significant. Example: 211.8 = 4 SF  Significant Figure Rules 2. All zeros that are found between nonzero digits are significant.  Significant Figure Rules 2. All zeros that are found between nonzero digits are significant. Example= 20,007 = 5 SF  Significant Figure Rules 2. All zeros that are found between nonzero digits are significant. Example= 20,007 = 5 SF  Significant Figure Rules 3. Leading zeros (to the left of the first nonzero digit) are not significant.  Significant Figure Rules 3. Leading zeros (to the left of the first nonzero digit) are not significant. Example: 0.0085 = 2 SF  Significant Figure Rules 4. Trailing zeros for a whole number that ends with a decimal point are significant.  Significant Figure Rules 4. Trailing zeros for a whole number that ends with a decimal point are significant. Example: 320. = 3 SF  Significant Figure Rules 5. Trailing zeros to the right of the decimal place are significant.  Significant Figure Rules 5. Trailing zeros to the right of the decimal place are significant. Example: 12. 000 = 5 SF  Significant Figure Rules 6. Exact numbers, and irrationally defined numbers like Euler’s number (e) and pi (π), have an infinite number of significant figures.  Significant Figure Rules 6. Exact numbers, and irrationally defined numbers like Euler’s number (e) and pi (π), have an infinite number of significant figures. Examples: π = 3.14  Significant Figure Rules 7. For any value written in scientific notation as A ×10x, the number of significant figures is determined by applying the above rules only to the value of A; the x is considered an exact number and thus has an infinite number of significant figures.  Significant Figure Rules 7. For any value written in scientific notation as A ×10x, the number of significant figures is determined by applying the above rules only to the value of A; the x is considered an exact number and thus has an infinite number of significant figures. Example: Significant Figures Significant Figures Significant Figures Significant Figures Significant Figures Operation Dealing with Significant Figures Multiplication and Division The rule is to count the number of significant figures in each number being multiplied or divided and then limit the significant figures in the answer to the lowest count. Operation Dealing with Significant Figures Multiplication and Division The rule is to count the number of significant figures in each number being multiplied or divided and then limit the significant figures in the answer to the lowest count. Operation Dealing with Significant Figures Multiplication and Division The rule is to count the number of significant figures in each number being multiplied or divided and then limit the significant figures in the answer to the lowest count. Operation Dealing with Significant Figures Addition and Subtraction Limit the reported answer to the rightmost column that all numbers have significant figures in common. Operation Dealing with Significant Figures Addition and Subtraction Limit the reported answer to the rightmost column that all numbers have significant figures in common. Operation Dealing with Significant Figures Addition and Subtraction Limit the reported answer to the rightmost column that all numbers have significant figures in common.  Significant Figures How many significant figures does the following numbers have? 1. 2. 0.00057262 3. 123. 4. 00001420 5. 12.124 Operation Dealing with Significant Figures