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### Course: Pixar in a Box>Unit 7

Lesson 2: The physics of particle systems

# Graphing motion over time

We can describe motion, control collisions, and track motion over time using position, speed, and acceleration. Learn how these change with time, in particular when gravity is involved. Speed is calculated as the change in position over the change in time, whereas acceleration is the change in speed over the change in time.

## Want to join the conversation?

• why do we have to divide?
• It's a rate. A rate represents a ratio, which is better described as a fraction.
• What's the point of knowinng acceleration, if acceleration is constant due to gravity?
(1 vote)
• g=9.8 m/s2 is a fact
However, if the particles bounce into each other or get blown away, their acceleration won't be constant anymore. The acceleration may decrease and increase according to other rules of physics ^^
• I'm sorry but what the heck is this? i am heading into high school and i love coding, so far this only consist of graphs. I'm here to code(sorry)
• i dont understand anything
• I have absolutely no idea what this even means. Can someone please explain this to me in simpler terms?
• This video is just saying that you will learn how to simulate the position, velocity, and acceleration of your particle system. Remember that ball in the video? We are going to be doing the same thing. But first you have to learn how to make it look realistic in the whole animation, which is where you have to learn how to make the position, velocity, and acceleration of your animation/particles look real!
• Why are the effects listed before animation in the content list if you have to reffer to like that?
• Its been organized as best it can be, the small reference in this video was brief and easy to pick up during the course of the video.

Its amazing we even have these in the first place, organization is the least of my concerns.
• hey duskpins what is up
(1 vote)
• what is a duskpins?
• how old are all the fricking peeps here
(1 vote)
• Neither 6 To 10
(1 vote)
• whats this
(1 vote)
• It's particle motion, to be specific, its "Graphing motion over time" Is there anything you don't understand that I could try and answer?
(1 vote)
• no questions.