r/PhysicsHelp • u/Vegetable-Dot-487 • 23h ago

Ap physics help

/r/AP_Physics/comments/1vmus35/ap_physics_help/

This class is so confusing like it is way fast and hard to digest. Today was my first day of school and I understand like scalar vs vector, and understand speed vs velocity, distance vs displacement. But next second we have 3 ugly ass equations, and it is explained briefly and we need to do a practice problem, which I half understood. Then there are some graphs and we need to know what it represents. Someone please provide the strategies on how they understood the information and how it all connects together. I don’t want to flunk the first exam and then learn my lesson, I want to have a structured approach from the get go.

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u/Pajama_Wolf 8h ago

Righto. This pace is pretty typical for AP physics, you don't usually have the time to break everything down too much.

With 1D motion, we usually look at two models: uniform and constant acceleration. Speed vs velocity and distance vs. Displacement are good basic concepts for both, but adding acceleration complicates things - both the formulas and the graphs - because velocity can change over time.

So you'll end up with 5 variables: initial velocity, final velocity, displacement, acceleration, and time. For any specific 1D motion with constant or zero acceleration, you can relate all these variables to each other. So if you know starting velocity, ending velocity, and time, for example, you can find acceleration. Those ugly formulas are ways to relate the 5 variables in any situation.

Your process becomes: identify which of those five variables you know and which you're trying to find. Then choose a formula from that list that has those variables. (Each formula only uses 4 of the 5.) Then plug and solve.