Key Concepts in Physics: Motion, Heat, and Energy
Angular Motion
Equations of angular motion are relevant wherever you have rotational motions around an axis. When an object has rotated through an angle of θ with an angular velocity of ω and an angular acceleration of α, then you can use these equations to tie these values together.
You must use radians to measure the angle. Also, if you know that the distance from the axis is r, then you can work out the linear distance traveled, s, velocity, v, centripetal acceleration, ac, and force, Fc. When
Read MoreUnderstanding Electricity: Static, Current, Circuits, and More
Topic 1: Early Models of Electricity
Two-fluid model (late 1700s) (Dufay)
- Explained two kinds of charges caused by varying amounts of two fluids called vitreous and resinous.
- A neutral object had equal amounts of both fluids.
One-fluid model (1752) (Franklin)
- Explained a charged object as having an excess or deficiency of electrical fluid.
- A neutral object would have the proper amount of fluid.
Topic 2: Atomic Structure and Charge
- Atoms are made of subatomic particles such as protons, which are stationary,
Understanding Electrostatics: History, Matter, and Laws
Electrostatics: An Introduction
Electrostatics: It is the branch of physics that studies the phenomena of electricity produced by static charge distributions, i.e., the electrostatic field of a charged body.
Historical Development
Around 600 BC, the philosopher Thales of Miletus noted the ability of amber, after being rubbed, to exert attraction on small objects. Somewhat later, another Greek, Theophrastus (310 BC), undertook a study of the different materials that were capable of producing electrical
Read MoreUnderstanding Waves: Types, Properties, and Phenomena
Transverse and Longitudinal Waves
Transverse Wave (e.g., Light): Vibrations are perpendicular to the direction of wave motion.
Longitudinal Wave (e.g., Sound): Vibrations are parallel to the direction of wave motion.
Key Wave Properties
- Wavelength: The distance between any two corresponding parts of the wave.
- Amplitude: The maximum distance the wave moves from the equilibrium position.
- Frequency: The number of waves per second.
- Period: The time taken for one complete wave to pass a point.
Wave Phenomena
Diffraction
Diffraction:
Read MoreThermodynamics: Key Concepts and Applications
Fundamental Principles
Under what thermodynamic condition is the change in enthalpy equal to the heat transferred into a system? Constant pressure.
The entropy is associated with what qualitative feature of a system? Disorder.
List two general categories of energy storage at the atomic and molecular level, for subsequent access by cellular biochemistry:
- (1) Chemical reactions [bond formation and breaking]
- (2) Chemical bonding and interactions [molecular recognition]
True or false: Temperature is an extensive
Read MoreUnderstanding Key Physics Principles and Theorems
Steiner’s Theorem
Determining the moment of inertia about an axis of symmetry can be quite complicated by integration. Steiner’s Theorem simplifies this determination. It provides a relationship between the moment of inertia about an axis through a random point of the plane and the moment of inertia about a parallel axis through the center of mass.
Ie = ∫ (x² + y²) dm = ∫ [x² + (d + y)²] dm = ∫ (x² + y²) – 2dy dm + d² ∫ dm = Iz + Md²
Graphical Determination of Instantaneous Center
a)
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