https://youtu.be/Upt3FM5Iv2w
PHYS 1101: Lecture Seven, Part One
Welcome everyone to Lecture 7. This lecture is going to prepare us for doing the same type of thing we did in Chapter 2 but now applying it to the motion in what we call two dimensions or studying the motion now where trajectories can be curved.
Real quick, a visual of that is Chapter 2, we were restricted to motion diagrams along the line. And now in Chapter 3 we can have curved trajectories following any kind of path or curve. And what are the mathematical variables now that we need to describe this motion, and how do we go about it?
It’s going to be very similar to Chapter 2. We just really need to extend it to one new level of complication. To build up to that, I want to start out and talk more about motion diagrams. For one dimensional motion, I think you appreciated how valuable they were at visualizing these critical vector quantities and their direction. And that’s going to be just as true in Chapter 3.
After we do the motion diagrams, then I’m going to introduce you to these fundamental vector quantities that we need to describe this two dimensional motion.
Let’s start out, as always, with a warm-up quiz question, and here I ask you which motion diagrams shows constant acceleration. It can’t be 0. It has to be some constant amount.
What does that mean? Remember that acceleration, looking for the amount of acceleration on a motion diagram is equivalent to looking for these delta-v vectors, these change in velocity vectors, the difference between two subsequent velocity vectors.
What’s the difference between any of these pairs? You’re looking for the case where that delta-v is the same between all snapshots of this motion diagram will mean constant acceleration. And, again, five points for everybody if the majority of you get it right, plus one otherwise.