SCI340_L01_fundamentals SCI 340 Welcome to Physics SCI 340

What’s the Point? Physics is basic Physics explains things Physics is the secrets of the universe

Topics Semester 1 Kinematics: describing motion Mechanics: Explaining motion Force and motion Common types of motion Conservation laws: What Nature cares about Thermodynamics: Small things in Quantity Heat and temperature Kinetic theory

Topics Semester 2 Entropy: why anything happens Fluids Density and buoyancy Fluid flow Electricity and Magnetism Forces Circuits Electric power

Topics Semester 2 Light Nuclear Physics Electromagnetic waves Color Optics Nuclear Physics Radioactivity Fission and fusion

Who are You? Please clearly write your first and last name on the tent card Your Name Please bring your tent card to every class First Last

Group Work Introduce yourself to your group. Identify something memorable about yourself your home town your family your name or anything else associated with you Tell your group and write it down.

The fundamental quantities The Science of Physics The fundamental quantities

Indefinable Fundamentals Distance Mass Electric charge Time

Distance Defined circularly with length Length: the distance between specified locations Distance: the length of a line segment joining two points American Heritage Dictionary, 1981.

Mass 6. The measure of a body’s response to acceleration. The mass of a body is different from but proportional to its weight, is independent of the body’s position but dependent on its motion with respect to other bodies, and may be expressed in mass units, such as kilograms or slugs, or corresponding energy units, by means of the mass-energy relationship of the special theory of relativity. American Heritage Dictionary, 1981.

Charge 14a. The intrinsic property of matter responsible for all electric phenomena, in particular for the force of the electromagnetic interaction,occurring in two forms arbitrarily designated negative and positive. American Heritage Dictionary, 1981.

Time A nonspatial continuum in which events occur in apparently irreversible succession from the past to the present to the future. An interval separating two points on this continuum, measured essentially by selecting a regularly occurring event, such as the sunrise, and counting the number of occurrences during the interval’s duration. American Heritage Dictionary, 1981.

Fundamental Units Quantity Unit Distance meter (m) Mass kilogram (kg) Charge coulomb (C) Time second (s) SI (International System) or MKS units

Fundamental Units All units we will encounter are defined in terms of the fundamental m, kg, C, and s.

Working with Units Math makes sense

Eat a live bullfrog first thing in the morning… …and nothing worse will happen to you for the rest of the day!

Do math with units Unit labels can be treated like any variable in algebra. Add them! 3 x + 4 x = 7 x 3 s + 4 s = 7 s Divide them! = 3 x/y 6 x 2 y Multiply them! (3a)(4b) = 12 ab (3 m/s)(4 s) = 12 m = 3 C/s 6 C 2 s

Compound Units Represent: Areas Volumes Accumulated effects Effects of population

Compound Units a Area = ab b

Compound Units Effort = (3 w) (4 h) = 12 (w)(h) = 12 worker·hours 3 workers 4 h

Ratio Units Represent: Rates of change Intrinsic properties

Ratio Units A baby has a mass of 3.2 kg at birth and 8.6 kg 9 months later. What is its average annual growth rate during this time? 5.4 kg 0.75 y slope = = 7.2 kg/y mass (kg) time (y) 10 8 6 4 2 1 0.75 y 5.4 kg

Manipulating Units Conversions 39.37 in = 1 m equality = 39.37 in 1 m conversion factors = 72 in · 1 m 39.37 in = 72 39.37 m 72 in = 72 in · 1 = 1.829 m

Group Work 1 mi = 5280 ft 1 yd = 3 ft Set up the conversion 2 mi to yd. 1 mi = 5280 ft 1 ft = 12 in 1 m = 39.37 in 1 h = 3600 s Set up the conversion 75 mi/h to m/s.