Beginning physics question?

Question

I'm barely starting physics, and the book I needed for the class isn't in, have a two week wait.

I just need help with reading graphs, such as this one: http://i299.photobucket.com/albums/mm320/waterpologoat/physics.jpg

I'm supposed to figure out where in the graph "the speed is increasing, and the position is decreasing." (You have all options, a-b, b-c, c-d etc. or none of the above.) There are a bunch of questions about position and speed, then there are questions asking "when is acceleration positive? Negative?"

I'm failing miserably in reading the graph. How do i know? It's an online assignment, and I only get two tries per question. If you could shed some light on this for me, you'd be a life saver!

Answer 1

You will do just fine!

When the line is straight, you are not accelerating.

So, from A to B and D to E your decelerating to get ready to change directions (negative).

From B to C and E to F you are accelerating back in a new direction (positive).