Claire Conger

I just finished listening to Great Ideas of Classical Physics CDs (The Great Courses). At first I thought I wouldn’t be able to listen to it, but about fifteen minutes in, Steven Pollock’s voice took on a soothing familiarity that made me want to hear more.

Professor Pollock explains physics basics I’d never understood. Wow!

I can now explain why two objects of similar aerodynamics but different weights fall to earth at the same speed.

Gravity exerts a greater force on the heavier one, so it should fall faster, shouldn’t it? Aristotle thought so. But it doesn’t because the heavier one takes more force to get it going. (An object at rest wants to stay at rest.) The extra force it takes to get the heavier object going is exactly equal to the extra force with which gravity pulls. Voila!

I also now know why my father’s explanations of centrifugal force never made any sense. (I’m not stupid after all!)

Professor Pollock explains that centrifugal force is what we call what we feel when we feel centripetal force. There’s really no such force as centrifugal! Centripetal force is pulling us toward the center of a circle, like in a car going too fast around a curve and we feel as if we’re being thrown to the outside. We’re not being thrown out, it’s that our bodies want to continue forward in a straight line. There is no outward force–the only force is the machinery of the car pulling us in. Voila!

These are such simple ideas, I should have learned them in elementary school.

(This CD set, Great ideas of Classical Physics, is twelve lectures long. It covers the basic laws of motion and gives a short history of the usual dead white European male activity, most particularly that of Isaac Newton.)