What is Physics?

1. What is Physics?

2. What is Physics? • Physics is • the scientific study of the physical world: matter, energy, motion, and force. • The study of the fundamental laws of nature, which, simply put, are the laws that underlie all physical phenomena in the universe. • From a Greek term meaning "the science of nature."

3. What is Physics? Continued • Physics is everywhere, in fact most people know more about it than they think they do • When you buy ice cream you know that you need to put it in the freezer. Why? Because it would melt otherwise. • Any problem that deals with temperature, size, motion, position, shape, or color involves physics. • We have remarkably found that these laws can be expressed in terms of mathematical equations.

4. Areas within Physics

5. This is Physics!!

6. SI Units

7. SI Prefixes • Prefixes are used to change the size of the base unit. Used instead of writing a lot of zeroes.

8. Conversion Factors • Conversion factor • A ratio of equivalent measurements. • Useful in solving problems in which a given measurement must be expressed in some other unit of measurement.

9. Dimensional Analysis • Dimensional analysis • A way to analyze and solve problems using the units of the measurements.

11. Converting Between Units

12. Multistep Problems

13. Converting Complex Units

14. Practice Problems • A minivan sells for 33,200 dollars. Express the price for a minivan in kilodollars and Megadollars? • A Typical E.coli bacterium is about 5 micrometers in length.Give the length in millimeters and kilometers. • How many seconds are in a leap year? • Convert the speed 5.30 m/s to km/h.

15. Scientific Notation • Scientist often deal with very large or very small numbers. These numbers can be expressed in powers of 10 • Numbers take the form of • M X 10n • Where M = a number 1 – 10 • And n = the number of decimal places moved

16. Conversions usingScientific Notation with large numbers • Ex 1 • Convert 1,500,000 to scientific notation. • First move the decimal place so that there is only one digit to its left • 1.5 • How many spaces did we move them? • 6 • So we write it as • 1.5 x 106

17. Conversions using Scientific Notationwith small numbers • Ex 1 • Convert .000025 to scientific notation • First move the decimal • 2.5 • How many places did we move it? • 5 • So we write it as: • 2.5 x 10-5 (note: since the number was less than one it is written as a negative number)

18. Sample Problems • Convert the following: • 5.65 x 106 • 4.90 x 10-4 • .000000045 • .0000067

19. Using Scientific Notation • Multiplication • The base numbers are multiplied and the exponents are added. • (4.0 x 103)(2.0 x 103) = • Division • The base numbers are divided and the exponents are subtracted. • (1.06 x 104)/(2.0 x 10-2) = • Addition or subtraction • Express all the exponents in the same power of 10. Perform the addition or subtraction, then if necessary convert to correct form of scientific notation. • 7.11 x 104 + 4.0 x 103 =

20. Significant Figures(Sig Figs) • All Digits 1-9 are significant • 129 • 3 sig figs • Zeros between significant digits are significant • 5,007 • 4 sig figs • Trailing zeros are only significant if the number contains a decimal point • 100.0 • 4 sig figs • 100 • 1 sig fig • Zeros in the beginning of a number whose only function is to place the decimal points are not significant • 0.0025 • 2 sig figs • Zeros following a decimal significant figure are significant • 0.000470 • 3 sig figs • 0.47000 • 5 sig figs

21. Calculations using Sig Figs • When multiplying or dividing • Round to the least number of sig figs • When adding or subtracting • Round to the least amount of decimal places

22. Sample Problems • 6.201 cm + 7.4 cm + .68 cm + 12.0 cm • 10.8 cm - 8.264 cm • 139 cm x 2.3 cm • 18.21 g  4.4 g

23. Today’s Homework • Page 9 • 1, 2 • Page 20 • 1, 2, 3, • Pages 27 – 31 • 1,2,5,7,8,11,13,16,18,19,20,21,22