# One-Dimensional Motion (Linear Kinematics)

### Instantaneous vs Average Velocity

#### In this video, first I explain the difference between these two types of problem. Then we'll go through a bunch of questions and just look at the wording to figure out if you're supposed to solve them using the average velocity equation (V_{avg}=ΔX/Δt) or the more common instantaneous velocity equations from kinematics.

### Average Velocity Problems

*V*_{avg}=ΔX/Δt or V_{avg}=(V_{i}+V_{f})/2

_{avg}=ΔX/Δt or V

_{avg}=(V

_{i}+V

_{f})/2

#### First, this video shows you how to use the first equation above to solve basic average velocity problems. Then I show you how to use the second equation to solve a particular type of trick question where they don't use the word "average" in the problem but most profs expect you to be able to solve. I also let you in on how to use the average velocity formulas above to solve almost any kinematics problem, which not everyone likes but some of my students really latch onto.

### Units of Acceleration Explained

#### m/s²? How the heck can you square seconds? And calling them "meters per second per second" is even worse! This formula-free video explains all that. To help you get your head around these funky units, I start with a few basic problems using non-metric units that actually make a bit of sense to normal people.

### Formula-Free Acceleration & Velocity Problems

#### For most physics students I work with (i.e. the normal, non-A+ people), physics isn't the problem: it's the formulas that confuse them and induce panic. So if you're not loving physics, I encourage you to watch this video, where we'll solve a few problems with common sense rather than getting lost in plug-and-chug land. Then in the next videos when we do the harder problems with formulas, hopefully the background in this video will give you a little bit more understanding and a little less panic.

### 1-D Vertical (Gravity) Kinematics Problems

*V=V*_{0y}+gt & Y=Y_{0}+V_{0y}t+½gt²

_{0y}+gt & Y=Y

_{0}+V

_{0y}t+½gt²

#### This video covers one-dimensional problems where an object is either dropped or thrown vertically, i.e. straight up or straight down. No angles. No horizontal components. Just answering questions like "how long does a rock take to hit the ground when dropped off a 40-m tall building?" "What if it's thrown downwards at 20 m/s?" "What if it's thrown up at 30m/s?"

### Horizontal 1-D Kinematics Problems

*V=V*_{0}+at & X=X_{0}+V_{0}t+½at²

_{0}+at & X=X

_{0}+V

_{0}t+½at²