Physics- The basics Mrs. Schwartz 2016

Physics- the basics What is physics? the branch of science concerned with the nature and properties of matter and energy. Includes: mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.

Falling objects, friction, weight, spinning objects Areas Within Physics Name Subjects Examples Mechanics Motion and its causes Falling objects, friction, weight, spinning objects Thermodynamics Heat and temperature Melting and freezing processes, engines, refrigerators Vibrations and wave phenomena Specific types of repetitive motions Springs, pendulums, sound Optics Light Mirrors, lenses, color, astronomy Electromagnetism Electricity, magnetism, light Electrical charge, circuitry, permanent magnets, electromagnets Relativity Particles moving at any speed, including high speeds Particle collision, particle accelerators, nuclear energy Quantum mechanics Behavior of submicroscopic particles The atom and its parts

The scientific method

The scientific method Observations/Question Hypothesis: Experiment Collect data Interpret/analyze Conclusion:

Measurements SI units = never leave your number naked! 5means nothing! 5m means something Do you remember the si units for the following? Length Time Mass Volume

prefixes

Conversion factors Ex 1m =100cm Helps us with dimensional analysis

Scientific notation express the very large and the very small numbers so that problem solving will be made easier. Examples: The mass of one gold atom is .000 000 000 000 000 000 000 327 grams. One gram of hydrogen contains 602 000 000 000 000 000 000 000 hydrogen atoms.

Practice Problems ANSWERS PROBLEMS 1.2 x 10-4 1 x 103 1 x 10-2 Put these numbers in scientific notation. PROBLEMS 1.2 x 10-4 1 x 103 1 x 10-2 1.2 x 101 9.87 x 10-1 5.96 x 102 7.0 x 10-7 1.0 x 106 1.26 x 10-3 9.88 x 1011 8 x 100 ANSWERS .00012 1000 0.01 12 .987 596 .000 000 7 1,000,000 .001257 987,653,000,000 8

EXPRESS THE FOLLOWING AS WHOLE NUMBERS OR AS DECIMALS PROBLEMS ANSWERS 4.9 X 102 3.75 X 10-2 5.95 X 10-4 9.46 X 103 3.87 X 101 7.10 X 100 8.2 X 10-5 490 .0375 .000595 9460 38.7 7.10 .000082

Sample Problem: Multiply (3.2 x 10-3) (2.1 x 105) Multiplication When multiplying numbers written in scientific notation…..multiply the first factors and add the exponents. Sample Problem: Multiply (3.2 x 10-3) (2.1 x 105) Solution: Multiply 3.2 x 2.1. Add the exponents -3 + 5 Answer: 6.7 x 102

Sample Problem: Divide (6.4 x 106) by (1.7 x 102) Division Divide the numerator by the denominator. Subtract the exponent in the denominator from the exponent in the numerator. Sample Problem: Divide (6.4 x 106) by (1.7 x 102) Solution: Divide 6.4 by 1.7. Subtract the exponents 6 - 2 Answer: 3.8 x 104

Addition and Subtraction To add or subtract numbers written in scientific notation, you must….express them with the same power of ten. Sample Problem: Add (5.8 x 103) and (2.16 x 104) Solution: Since the two numbers are not expressed as the same power of ten, one of the numbers will have to be rewritten in the same power of ten as the other. 5.8 x 103 = .58 x 104 so .58 x 104 + 2.16 x 104 =? Answer: 2.74 x 104

Sig figs- ugh Measurement that consists of all known digits with an uncertain digit at the end Uncertain digit The digit that you as the experimenter must estimate

Sig fig rules

Sig fig math Adding and Subtracting Multiplying and Dividing Answer must have the same number of digits to the right of the decimal point as there are in the measurement having the fewest digits to the right of the decimal point. 2.59 + 6.8974 = 9.49 Multiplying and Dividing Answer can have no more significant figures than are in the measurement with the fewest number of significant figures. 3.05/8.47 = .360

Examples How many significant figures? Solve 28.6g 3440. cm 910m .067000kg Solve 5.44m – 2.6103m = 2.4g/mL x 15.82 mL =