Just Who Gave Me This Cold?

Someone is going to get the stink-eye from me if I find out who transmitted their plague germs into my personal bubble. Hopefully, I shall not be brung low by this pestilence, but we shall have to see. I am made of stern stuff, after all...

Physics A and B Blocks have been marching through Newton's laws of motion and a few specific forces. Remember that Newton's laws of motion state what objects do when exposed to a zero or non-zero net force and also point a finger at the culprit(s) providing that force. Two of those culprits could be weight and the normal force. Weight is the action of gravity on an object's mass and the normal force is the response of a surface to a press onto it. That response is always perpendicular to the plane of the surface and may or may not line up with the object's weight (which is always straight down). We looked at how to calculate the normal force acting on an object and we'll check over that work tomorrow before diving into friction. Exam coming up next Tuesday and we have a lab to conduct on Newton's 2^nd law in the interim, so start gathering questions and making study preparations so you can do your best on the test.

Honors Physics has been discussing the concepts of work and energy. We disentangled the scientific definition of work from how the term is used in daily life and identified examples where objects were having work done on them by a force and when a force was not doing work on the object. W_net was linked to an object's motion and change/lack of change of motion and further linked, today with the change in energy an object experiences. We defined kinetic, gravitational potential and elastic potential energy and discussed how a change in each of them related to the work that was done on or by an object. We'll look at this some more tomorrow before moving more deeply into energy territory.

Introductory Physics has been laboring with gravity. We looked at Newton's law of universal gravitation yesterday from a conceptual and mathematical standpoint and, today, added in the concepts of free fall, weight and acceleration due to gravity. Remember that free fall only applies when there isn't another force acting on the object's motion besides gravity, such as air resistance, so it isn't applicable to all circumstances. However, many objects moving through the air do approximate free fall and it can be a good predictor for features of the object's motion, such as how high the object rises when thrown upwards or fast it will hit the ground when it is dropped. We'll practice with this idea tomorrow and begin to look at a slightly more complicated model of motion - projectile motion.