Lesson 02

Moment -- or, a tendency to rotate

🟦  2.1  What is a moment?

Today we will learn one of the most important concepts we will need to solve Statics problems. It is a little abstract -- at least, more abstract than thinking about forces. For that reason, sometimes students are reluctant to engage with this new concept. So, I want to start this lesson by being crystal clear about one fact: you will have to use moments in almost every problem in this course.

Browse the flipbook for an introduction to this new idea. In the next few sections, we'll learn about two ways to think of moments:

Flipbook or Animation: Introduction to Moments

🟦  2.x  Visualizing the rotation of a body about an axis

x pushpin analogy (or, using your left hand to hold a pen, which is the axis, and your right hand to figure out the sign)

🟦  2.x  Translational Motion + Rotational Motion = MOTION




❏ Flipbook: x!)



🟦  2.x  Moment as lever (types of levers)

Class 1: seesaw or pliers

Class 2: nutcracker

Class 3: tweezers

❏ Animation: Types of Levers


🟦  2.x  Wait a minute - isn't this just torque (from Physics?)

In Physics, you learned that a torque is equal to the product of a force and a distance.

🟦  2.x  Force couples (and explain why I always put "forces (and moments)" as a parenthetical note)

this is a super abstract concept so be super explicit here.

➜ Practice Problems

coming soon

seesaws? lots of them?