Circuit simulator
https://phet.colorado.edu/en/simulation/circuit-construction-kit-dc
Posts
HW solutions
Charge HW to submit on Friday 1. What exactly IS charge? How do we think of it? How does it relate to protons, electrons, etc.? A way of quantifying how particles interact with each other, based on the amount (and imbalance) of protons and electrons. Neutrons have zero charge. Electrons have opposite charge relative to each other. 2. Which particles in an atom are easiest to move, and why? Electrons, as they are "around" the nucleus of the atom. 3. What does atomic number (H = 1, He = 2, etc.) mean? The number of protons in the nucleus of the atom. 4. What are quarks Fundamental particles, incapable of being broken up further. There are 6 types, 2 of which (up and down) make up protons and neutrons. 5. Coulomb’s law is an “inverse square law” – what...
Charge! (The details.)
Intro to electricity Electricity I - Charge! Charge - as fundamental to electricity (& magnetism) as mass is to mechanics Charge is a concept used to quantatively related "particles" to other particles, in terms of how they affect each other - do they attract or repel? If so, with what force? Charge is represented by letter Q. The basic idea - likes charges repel (- and -, or + and +) and opposite charges attract (+ and -). Charge is measured in units called coulombs (C). A coulomb is a huge amount of charge, but a typical particle has a tiny amount of charge: - the charge of a proton is 1.6 x 10^-19 C. Similarly, the charge of an electron is the same number, but negative, by definition (-1.6 x 10^-19 C). The negative sign distinguishes particles from each other, in terms of whether or not they will attract or repel. The actual sign is arbitrarily chosen. The charge of a neutron is 0 C, or neutral. But what IS charge? Charge is a bit difficul...
Standard Model of Particles and Interactions
For next class, try to explain the pom-pom demonstration. Also, have a look at this chart and note anything interesting. http://electron6.phys.utk.edu/phys250/modules/module%206/images/particle_chart.jpg
Newton's 3rd Law
Lex. III. Actioni contrariam semper & aequalem esse reactionent: sive corporum duorum actiones in se mutuo semper esse aequales & in partes contrarias dirigi. To every action there is always opposed an equal reaction; or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts. Whatever draws or presses another is as much drawn or pressed by that other. If you press a stone with your finger, the finger is also pressed by the stone. If a horse draws a stone tied to a rope, the horse (if I may so say) will be equally drawn back towards the stone: for the distended rope, by the same endeavour to relax or unbend itself, will draw the horse as much towards the stone as it does the stone towards the horse, and will obstruct the progress of the one as much as it advances that of the other. And now, in more contemporary language: 3. Newton's Third Law To every action, there is opposed an equal reactio...
Isaac Newton, 1642-1727 Principia Mathematica, 1687 Newton, Philosophiae naturalis principia mathematica (1687) Translated by Andrew Motte (1729) Lex. II. Mutationem motus proportionalem esse vi motrici impressae, & fieri secundum lineam rectam qua vis illa imprimitur. The alteration of motion is ever proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed. If any force generates a motion, a double force will generate double the motion, a triple force triple the motion, whether that force be impressed altogether and at once, or gradually and successively. And this motion (being always directed the same way with the generating force), if the body moved before, is added to or subtracted from the former motion, according as they directly conspire with or are directly contrary to each other; or obliquely joined, when they are oblique, so as to produce a new motion co...