Chapter 1 An Introduction to Physics

1. Chapter 1An Introduction to Physics

2. Part 1: An Introduction to Physics • Physics is the study of matter, _________, and change. • Physics is a guide to actions in the complex world of natural phenomenon.

3. 1.1 Law and Theory • Natural phenomena occur in reproducible ways. • A is a description of a relationship in nature that appears in recurring patterns of events. • It can be a prescription of how things change, or it might be a statement of how things resist .

4. __________ is the explanation of phenomena in terms of more basic natural process and relationships. • To explain phenomena, we draw on intuition, imagination, and guessing at what is happening. we call this a . • A construct of definitions, hypotheses, and laws that explain some observed order in nature is called a .

5. A powerful theory allows us to work with known laws as well as to predict new occurrences and relationships that, once tested and confirmed, may become new laws. • All theory is . Our current world view may be wrong. Our hypotheses may be in error, our laws only approximate. • Newton’s mechanics worked amazingly well for over 200 years. ________ proved our view was a brilliant approximation of a more complete truth.

6. 1.2 The Modern PerspectiveClassical Physics • Classical Physics was what we knew until the _______. • This included the disciplines of Newtonian mechanics, thermodynamics, and electromagnetic theory. • By the time Einstein presented his general theory of relativity, we were able to understand curved space-time, black holes, pulsars, and the ____________ creation of the universe.

7. Atomic Theory • All matter is made of atoms. These tiny particles have a very _____ attraction that holds them together. • In fact, when they are close to other atoms, they can attract to form __________. • If they are more then a few atomic nuclei apart, they will not interact at all. • This causes them to repel, so well, that they push apart. This creates what we perceive as a ________ surface.

8. Atoms are in never ending motion. • That is why atoms that make up a ____ can create their own pressure. • As atoms gain and lose energy they expand and contract in _________. • We now know atoms are made up of even smaller particles.

9. Quantum Physics • In 1905 Einstein showed light was a particle we now know as a _________. • An atom’s electrons are made up of leptons. While its protons and neutrons are made up of ______. Three for each particle. • Atoms absorb and lose _______ by gaining and losing photons.

10. Each proton and neutron is composed of three smaller rotating particles called quarks.

11. Since the 1920’s, a new area of study came to be known as Quantum Mechanics. • Scientists use large particle ____________ that smash particles together at near light speed. This possibly simulates conditions that may have existed in our early universe.

12. The Four Forces • Scientists recognize four forces. In this sense we will define force as an agent of change. • Gravity is the _________ of the forces, however it has unlimited range. • It holds our planet and all the things on its surface down. It holds our planet in orbit around our sun. It can only _____, not repel. • If it were any stronger than it is, our universe would begin to pull in on its self stopping our current expansion.

13. The electromagnetic force holds atoms, molecules and all the structures we perceive together. • But it can also _______ as well. This is the same force we experience with __________. • Its range is also unlimited. Without its repulsive ability, gravity would crush all things together.

14. The strong force binds quarks together to form neutrons and protons. This force also holds the nuclei of the atoms together as well. • This is the _____ powerful force but has extremely ______ range. • This tiny range accounts for this force not influencing other aspects of atomic bonding.

15. The weak force is a million times fainter than the strong force and a 100 times shorter range. • It transforms one ______ into another. It can change a proton into a neutron. • It is responsible for the slow _____ of radioactive elements. • It allows our sun to undergo _______ inside its core.  Video

17. Part 1: Questions1. Einstein showed light was a particle we now know as a?2. To simulate conditions that may have existed in our early universe, scientists use large _______ accelerators. 3. T / F Gravity is the strongest of the forces, however it has very short range.4. The force a magnet produces represents which of the four forces?5. Which force binds quarks together to form neutrons and protons?

18. Part 2Measurement

19. Measurement • In Physics we use the _______ International or SI units. AKA the metric system. • These are some of the unit prefixes you will see on your formula sheet for the AP test.

20. Formulas like these, will be given as well.

21. 1.6 Significant Figures • There is no such thing as an ____ measurement. • When measuring, we look at the increments and estimate the last digit as close as we can. • This last significant number is usually estimated and known with the ______ certainty. • If our object is measured to 4.15 cm, then we have ______ significant figures.

22. 4.15 cm is the same as .0415 m. Again, 3 significant figures. • The number 1234 has __ significant figures. The number 1000 can have four significant figures or only one. Usually it will be written as 1.000 x 103 • Zeros after a digit usually are ___ significant, like 146,000,000. Zeros before digits are not significant like 0.0001. Zeros to the _______ of a decimal number are, like .0012300.  Video

24. Processing Significant Figures • To work out computations we must convert everything to the ______ system. • The AP test will only use S.I. units. Nothing will need to be converted. • Next, make sure everything is in the same ____. Do not mix meters with centimeters, etc. • In multiplication or division, if you have a number with 3 significant figures and you multiply it with a number that only has two, your answer must be rounded to just two significant figures.

25. Rounding Video

26. Examples: 328 m x 14 m = 4592 m Round to … 4869.75 km / 151 km = 32.25 km Round to …

27. In adding or subtracting we keep our numbers in __________. • Our answers must be rounded to the lowest number of significant figures starting from the ___ side of the final answer.

28. Examples: 3002 m + 14.0 m = 3016 m Round to … 259.0 cm + 20.49 cm = 279.49 cm Round to …

29. Part 2: Questions1. The last significant number is usually ________ and known with the least certainty. 2. T / F Zeros before digits are not significant like 0.0001.3. If you have the number with 123 and you multiply it with 45, your answer must be rounded to… 5535 or 5500.4. In adding or subtracting, our answers must be rounded to the lowest number of significant figures starting from the (left or right) side of the final answer. 5. When rounding 54.7511 to 3 significant figures, it becomes?

30. End