Ch+1+-+Basic+Skills

**Basic Skills ([|Syllabus])**
= Chapter 1- Basic skills =

- Graphing

 * Physics ** is the study of energy and the forms of energy are mechanical, nuclear, thermal, electromagnetic, and chemical.



**Section 1- Symmetry**
Definition: making an object appear the same by flipping, turning, etc. Types: Rotational, Reflectional The Order of Symmetry is how many unique symmetries a something has. For example, an equilateral triangle has only 3 rotational symmtries. (ABC, CAB, BCA) For rotational, it includes the "do nothing," so a something will always have a rotational order of symmetry of at least 1. Reflectional does not include the do nothing, so it could have a reflectional order of symmetry of zero.

Rotational symmetry can be written as: R120º (ABC) = CAB Reflectional symmetry can be written as R1 (ABC) = ACB  Note: When there is more than one operation involved in symmetry, then the most recent operation is written to the left. ex. RI R120º (ABC) = CBA 2 1

*There are examples of symmetry all around us. Snowflakes and leaves are examples of symmetries in nature.

 **Section 2-Famous physicists** include Galileo who was sent to death for his belief of the sun being at the center of the universe, Aristotle, Newton, Einstein, and Stephan Hawking who speaks through computers about black holes. ,  Galileo; Aristotle; Newton; Einstein; Hawking Quick Facts About Each Galileo - Era of exploration, lived under house arrest, went blind from the sun Sir Isaac Newton - Friends with John Locke in England Albert Einstein - Developed the atomic bomb in the Manhattan Project, discovered the theory of relativity Stephen Hawking - Is a present day theorist

**Theory, Law, and Principle all describe natural behavior.** **Theory** is an explanation based in evidence. **Law** is an experimental description valid over a large number of tests about natural behavior and if one tests proves the law wrong, it is no longer a law. **Principle** is an experimental description valid over a large number of tests but delas witha very specific type of science.



Section 3-Standards and measurements
**True of any Standard?** **//Universally Understood//** **//Repeatable//**

**Metric System** began in 1795-French Standardized in 1960 __Fundamental__- a basic unit, defined, universally understood and repeatable __Quantity-__ amount of how much of a specific dimension, like the first word in the list of 7 Fundamental Units, listed below, but includes derived quantities such as speed and volume. __Unit-__ describes the size in which a quantity is measured like meter, foot __Derived__-combination of multiple fundamentals or more than one of the same like m/s or cm^3 All quantities other than those seven fundamentals are derived.

**The 7 Fundamental Units:** Length-meter Mass-kilogram Time-second Electric Current-Ampere Luminous Intensity-candela Temperature-Kelvin Amount of Sunstance-mole

Original units of meaure: digit, cubit, foot, hands, stone (Didn't work since unrepeatable)

**Systems of Measurement**

Newton(N)=kg*m/s^2, Joule(J)=Nm dyne=g*cm/s^2, erg=dyne cm pound=lb*ft/s^2, foot pound=ft*pound...
 * Quantities || Length || Mass || Time || Force || Work and Energy ||
 * mks (physics) || meter || kilogram || second || Newton(N) || Joule(J) ||
 * cgs (chemistry) || centimeter || gram || second || Dyne || Erg ||
 * fps (America) || foot || pound || second || Pound || Foot Pound ||



**Order of Magnitude** is a power of ten

**Prefixes** Larger: kilo (K) 10^3 Mega (M) 10^6 Giga (G) 10^9 Tera (T) 10^12 Peta (P) 10^15

Smaller: centi (c) 10^ -2 milli (m) 10^ -3 micro (µ) 10^ -6 nano (n) 10^ -9 pico (p) 10^ -12 femto ( f ) 10^ -15

media type="file" key="WikiVideo.mov" width="300" height="300" media type="custom" key="3142196"



Section 5- Significant Figures
Signifigant Digits/Figures are needed to get the accurate answer for every equation you do in Physics. __Rules:__Digits that are 0 and "trapped" in between other numbers **ARE** significantNumbers, including 0's, after the decimal, **ARE** significantAny real number **IS** significant0's after significant digits, but before an imaginary decimal can be significant, or not.

__When Adding:__ the answer should have the same decimal places ( numbers after the decimal) as the number with the least amount of decimal places when at the start of the problem.

__When Multiplying/Dividing:__ the answer should have the same amount of sig figs as the number with the least amount of sig figs in the problem. This is //total sig figs//, not just decimal places. media type="custom" key="3142206"

Section 6- Vernier Caliper
 It is used to measure lengths. It is extremely precise and accurate. The absolute error is smaller than that of a meter stick. For example, a meter stick’s error is about .05 cm give or take. A vernier caliper’s error is about .01 cm give or take. Therefore the vernier caliper is more accurate. The way to use it is actually pretty simple. First the jaws of the caliper are put around the object until it is held firmly into place. A picture of the scale is below. Next, the position of the line, A, is on the left. The line is called a marker. Read all the centimeters and tenths that are to the left of the marker. Below it is 2.2 cm. To get the last digit, find the line that lines up with the line from the scale. Then count until you reach the line. In the example below, the last line is 4. The reading is 2.24 cm + or - .01 cm.

Section 7- Trigonometry
**Equations** V=d/t c² = a² + b²

**Trig Functions (SOHCAHTOA)** sin ø = opposite/hypotenuse cos ø = adjacent/hypotenuse tan ø = opposite/adjacent *To undo a trig function sin^-1 (#)

(x,y)-rectangular coordinate system (x,theta)-polar coordinate system

**Absolute Error** Addition/Subtraction: add absolute error, decimal in same place in error as in the measurement Multiplication/Division: add percent error, answer is not a percent, so take absolute error divided by measurement equals percent error percent=absolute/measurement * 100% Absolute Error can only have only significant figure and it must be in the same place as the farthest right in the measurement. Percent Error may have two sigfigs (even if it is derived from an absolute error that must have only one).

Example: Given: a=5.5 cm b=8.4 cm  Find: c, A, B

To solve this, starting with c is the best idea. To find c, use the pythagorian theorum which is a^2+b^2=c^2. So 5.5^2 + 8.4^2 = 100.81. Take the square root of 100.81 which equals 10.04. c=10.04. SOHCAHTOA is the key to finding A and B. To find A, make A theta. Use the given measurements since they are more precise and accurate which are a and b. a is the opposite side to theta and b is the adjacent side. This means tangent is what is to be used. Tangent of A=a/b. The inverse tangent of a/b equals inverse tangent of 5.5/8.4. The answer is 33.2 degrees. To find B, make B theta. Using the given measurements, b is the opposite side and a is the adjacent side. Using tangent again since is it opposite and adjacent sides, it is Tangent of B=b/a. The inverse tangent of b/a equals inverse tangent of 8.4/5.5. The answer is 56.8 degrees.



**Section 8-Graphing**
Types of Lines: (But remember, lines are curves too!) direct (y=kx) *a direct graph goes through the origin! linear (y=kx+c) *k is the slope, and c is the y intercept.

Types of curves: Power Root inverse power (y=kx²) root (y=k(square root of x)=kx^½) inverse (y=k/x) these last three are not always perfect, i.e. power could be y=kx³

Straightening graphs:
To straighten a power, root or inverse graph, you change one variable, while keeping the other variable the same (normally x changes) For power graphs, take x to a power For root, take the root of x and for inverse, take the negative power of x  you may have to try a few different powers of x to get the right one!

= A side note- just a reminder = Some of the labs we did include the circle lab (indirect measurement), where we found a different way to measure (alternatives are always good!) The symmetry lab (wasn't graded) Density lab- found the density of 3 objects (practice using vernier caliper, sigfigs, and notebook) And finally, Hooke's law lab, using two different springs and finding the spring constant. It might be a great idea just to look over these worksheets in the chapter 1 link to remind yourself of the material!

** Good luck studying for your Midterm!!! ** ** This beautiful page was brought to you by Lindsey, Nate, Allura, and Regan :) **

= =