About Science & Physics
1. What is Science?
A systematic/methodical study of the world Falsification Technology = Applications
1. What is the Scientific Method
Observation: data collection. Hypothesis: proposed explanation Experimental testing. A
Class practice Problems (Chapter 2)
Problem 21: Along a straight road, a car moving with a speed of 130 km/h is
brought to a complete stop in a distance of 210 m.
a) Find the magnitude of the deceleration (assumed uniform)
b) How long does it take to stop
Chap. 32: The Atom
The 20th century was the century of the atom: man harnessed the "power of the atom", made atomic bombs, and generated electricity by nuclear power. He even split the atom into smaller pieces called subatomic particles. But
Chap 29 Atoms: excitations and emissions
Continuous Emission Spectrum
White Light Source
Emission Spectra of Hydrogen
Discrete Emission Spectrum
Low Density Glowing Hydrogen Gas
Chapter 28 Reflection & Refraction
Specular and Diffuse Reflection
Reflection from most surfaces is diffuse, with incoming light scattered in all directions. Reflection from mirror surfaces is specular, with light reflecting in one direction.
Chapter 27 Color
Spectrum of Visible Light
Wavelengths & Photons
Particles of light, called photons, have a wavelength.
Red Photon Yellow Photon Green Photon
Additive Color Wheel
Not in the spectrum. How do we see these? R
Properties of Light
Nature of Light
Light is an electromagnetic wave. It is a transverse wave, propagating at the speed of light: in vacuum v(light) = c = 300,000 km/s in other (transparent media): v(light) = c / n, where n is the "refraction i
Chapter 20 Sound
Nature of Sound
Sound is a wave that is produced by the vibrations of material objects.
Nature of Sound in Air
Sound in air is a longitudinal wave created by compressions and rarefactions.
Media which Tr
Chapter 19 Vibrations & Waves
Vibrations are a common phenomenon. They are oscillatory motions about some position of equilibrium.
Oscillating motion of a mass on a spring
The time required for a full oscillation (one round trip) is call
Projectile & Satellite Motion
A ball thrown across the room follows an arced trajectory. This is "projectile motion", which combines horizontal and vertical motion.
Projectile motion combines uniform horizont
Newton and the Moon
Newton realized that Earth's gravity was the centripetal force that kept the moon in orbit. He understood that gravity got weaker at larger distances.
Gravity & Distance
We don't notice that gravity gets
In physics we distinguish two types of motion for objects: Translational Motion (change of location) Rotational Motion (change of orientation)
Simple & Complex Motions
Motion of simple objects: Translation OR Rotation Motion of
Chapter 7 Energy
The "money" of physics.
Why Energy Helps
Motion, in general, is difficult to describe scientifically. Using forces, momentum, acceleration, etc. gets complicated because they are all vectors (have magnitude & direction). Energy is not a v
What happens when Object A hits Object B?
Momentum of an object is, Momentum = Mass X Velocity Examples of objects with large momenta are supertanker (large mass) and bullet (large velocity).
Momentum and Force
To stop an objec
Chapter 5 Newton's Third Law of Motion and Adding up Forces at angles
For every "action" there is a "reaction".
Newton's Third Law of Motion
Whenever an object exerts a force on a second object, the second object exerts a force of equal magnitude in the o
Chapter 4 Newton's Second Law of Motion
How does an object move when a force acts on it?
Force & Acceleration
Newton's First Law of Motion, Zero Force Definition of Acceleration, (Acceleration) = (Change in Velocity) (Time interval) Constant Velocity
(Motion in a straight line, such as falling straight downward)
Concepts you'll learn in this chapter
Speed and Velocity Acceleration Relationships among distance, velocity, and acceleration. Falling motion.
Define speed of a
Part I: Mechanics
Chapter 2 Newton's First Law of Motion
Aristotle & Galileo
Aristotle was great philosopher but not such a good physicist. Aristotle's theory of motion is wrong. Took 2000 years before Galileo got motion right.
Motion according to Aristo
Class practice Problems (Chapter 3)
Problem: While exploring a cave, a student starts at the entrance and moves the
following distances. She goes 75.0 m north, 250 m east, 125 m at an angle 30.0 north of
east, and 150 m south. Find the resultant displacem