Discussion of acceleration, including defining acceleration as a change in velocity, describing ways an object’s velocity can change and how those are analyzed qualitatively and quantitatively

https://app.fiveable.me/learn/ap-physics-1/acceleration/Ovn3Hbsyw481jPqxgssG

Not entirely sure if anyone still replies to these (or if it’s still legal to do so), but I’m doing some last-minute studying for my test, and I had lots of questions while watching the video:

- Graphs that show acceleration (Slide 11): Why was option 1 wrong exactly? It slows down exactly the way the question is asking us for, while Number two is showing an increase in velocity, rather than a decrease in velocity. It’s speeding up, not slowing down.
- Graphs that show acceleration (Slide 12): Wouldn’t the acceleration be positive if an object is speeding up, regardless of direction?
- Graphs that show acceleration (Slide 12): How do you exactly decide where to start your smiley or frowny face on the position x time graph?
- Graphs that show acceleration (Slide 13): Wouldn’t the acceleration be negative if an object is slowing down, regardless of direction?
- Graphs that show acceleration (Slide 13): Why is velocity positive? Shouldn’t it be going down, since it’s slowing down? Granted it’s on the negative quadrant, but it’s speeding up, not slowing down.
- Practice problems (Slide 16): Where did you get -.2? I understand the line goes negative, and I even tried to do all the divisions possible, but I still don’t know exactly how you got to that number.
- Practice problems (Slide 16): Why did you start at 0 for the penultimate line, but did not do the same thing on the first one that’s decreasing?
- Practice problems (Slide 17): Shouldn’t there have been a constant decrease in the graph from point 0-4 (time(s)), since the position was changing from 0,0?
- Practice problems (Slide 17): shouldn’t velocity be increasing at the beginning, and then decrease at the end, according to the position x time graph?
- Practice problems (Slide 17): Why is there a change in velocity on the equation (0-20), but not on time (it’s only 2, and not 0 +/- 2).

11: Practice problems (Slide 19): How is the object not at rest here? It contradicts what you said earlier in the video about point 0 in the y-axis meaning the object stays at rest.

I apologize in advance if any of these questions look dumb, or too obvious. I’ve never been great at physics, so this exam will be very hard for me. I’ll be watching more videos to study as well, so I apologize if any other notification pops up from videos from 6 months ago…