PHYSICS 101 (Physics for the Nonscientist) Dr. Anatoli Frishman frishman@iastate.edu Web Page: http://course.physastro.iastate.edu/phys101/

Introduction Course organization What is physics? A science A basic science The most basic science Discovered by several generations of scientists Physics and measurements Relationships between experiments and theory Mathematics - language of science Course organization Lectures Homework Exams (multiple choice) two midterm exams and a comprehensive final exam Formula sheet Syllabus

Physical quantities, units and standards What do we measure? - Physical quantities. Units - a unit is a measure of the quantity that is defined to be exactly 1. Examples: meter, mile, gram, kilogram. Standard - a reference to which all the other examples of the quantity are compared. Base quantities, and their standards. The International System of Units (metric system) Quantity Unit name Unit symbol Standard Length Meter m Distance traveled by light in 1/299,792,458 second Time Second s Time required for 9,192,631,770 periods of radiation emitted by cesium atoms Mass Kilogram kg Platinum-iridium cylinder in International Bureau of Weights and Measures at Sevres, near Paris

centimeter, gram, second 1m = 100cm 1kg = 1000g Other systems of units CGSE System of Units (metric system): centimeter, gram, second 1m = 100cm 1kg = 1000g British engineering system This system has force instead of mass as one of its basic quantities, which are feet, pounds, and seconds. 1 m = 3.281 ft; 1 inch = 2.54 cm 1 kg = 0.06585 slug (Not the same as weight!) on Earth 1 kg weighs 2.205 lb, on the Moon 1 kg weighs 0.368 lb

Conversion of units: Multiples of Units Multiply by the appropriate representation of 1 to cancel the unwanted units away Converting between metric units is easy, as it only involves powers of 10. Example 1: Convert 3kg into gram Multiples of Units 10-24 yocto- y 10-21 zepto- z 10-18 atto- a 10-15 femto- f 10-12 pico- p 10-9 nano- n 10-6 micro-  10-3 milli- m 10-2 centi- c 103 kilo- k 106 mega- M 109 giga- G 1012 tera- T 1015 peta- P 1018 exa- E 1021 zetta- Z 1024 yotta- Y Example 2: Convert 10 mph into m/s

Measurements and uncertainty When we measure something, there’s a limited accuracy: result  error (or accuracy) Example 1: 2.35  0.01 Example 2: Wrong: 2.35  0.1 Correct: 2.4  0.1 Significant figures Example 1: 0.24630 1sf 0.2 2sf 0.25 3sf 0.246 4sf 0.2463 5sf 0.24630 Example 2: Not so clear in some cases: 200 (1,2,3 ?) Scientific notation is crystal clear: 2  102 (or 0.2  103) 1sf 2.0  102 (or 0.20  103) 2sf 2.00  102 (or 0.200  103) 3sf

Physics Electromagnetism Optics Atoms & particles Mechanics Thermal properties Geometrical optics Wave optics Electrostatic Electric current Magnetism Condensed Mater High energy Biophysics Classical physics Quantum physics Relativistic physics Quantum relativistic physics

MECHANICS KINEMATICS 1. Motion Motion of what? Material point Kinematics is the study of motion, without the investigation of the cause of the motion 1. Motion Motion of what? Material point (An object with an irrelevant dimension for the purposes of a particular problem) Development of models Example: linear motion versus rotational Motion is relative to the object of reference Examples: the motion of an airplane passenger relative to the airplane, or the motion of an airplane passenger relative to the ground.

2. One dimensional (1D) uniform motion (Motion along a straight line with a constant speed) Example: Time interval: Distance: Speed: Note: In science, the capital Greek letter Δ means difference.

Uniform - motion with a constant ratio: Example: Given: Uniform - motion with a constant ratio: For uniform motion, velocity (v) is the displacement of an object over the time passed.

3. Speed a) Average speed: (total distance over total time) Definition: b) Instantaneous speed: Definition: Question: If the average speed is non-zero over some time interval, does this mean that the instantaneous speed is never zero during the same interval? A) Yes B) No C) It depends

Example 1 Given: A B Formula used: Solution: Answer:

Example 2 Given: Formula used: Solution: Answer: