Question

I need help with a velocity graph

Answer 1

http://i65.tinypic.com/2v0okgp.jpg

Answer 2

positive velocity means she was moving upward

Answer 3

remember that velocity is displacement/second
so if displacement is 0, it means 0 displacement/second, it was stationary

Answer 4

therefore
upward is when positive velocity
downward is when negative velocity
rest is at zero velocity

Answer 5

can u identify the intervals now?

Answer 6

Let me see...

Answer 7

Well, I thought that from (0,2) and (2,3) it was moving downward, but my teacher's work says that it was (2, 22/5).
How does that work?

Answer 8

I mean (0,1) and (2,3)

Answer 9

not 2,3

Answer 10

its not the slope that matters, its all the portion below 0

Answer 11

Oh....

Answer 12

after t=3 the velocity is still negative going to 0, that just means she was slowing down as she was walking backwards

Answer 13

So the particle is at rest from 1≤t≤2 ?

Answer 14

yes

Answer 15

Ok cool, I think I've got it. Thanks for clearing that up for me!

Answer 16

sure, one sneaky thing, u can ask ur teacher about it

Answer 17

at the point t=22/5, it is technically at rest, its an infintessimally small time frame, but i dont know how ur teacher wants to deal with that, its just logistics.

Answer 18

We're only on chapter 2, so I don't think we'll get that specific until some time in the future...

Answer 19

technically its not really an interval, so i think u can ignore that

Answer 20

ok, just wanted to throw that out there