Velocity Time graphs and Displacements

[amd123]

Homework Statement

How do i figure out the TOTAL displacement of this graph
http://img186.imageshack.us/img186/7677/36947032we7.jpg

Homework Equations

I'm guessing A=1/2bh
and A = bh

The Attempt at a Solution

I've got no idea due to the line crossing the X axis

 

[physicznoob]

ask yourself what velocities you're seeing. velocities include direction.

the Y - axis is telling you the velocity of the object, whereas the x-axis is telling you the time. you can tell the y-axis is velocity because of the negative values towards the bottom of the y axis. you can't see the negative values but they're there. remember the equation v = d/t :)

 

[physicznoob]

the line crossing the x-axis is simply the line that tells you the 0 point. it plays no significance unless your graphing line passes it. at the point that it passes that horizontal x-axis line, that would tell you your velocity is 0 m/s.

 

[The Motif]

This problem is quite common in classrooms. The answer, along with the proper work, can be found at "www.youtube.com/watch?v=Yu_moia-oVI"[/URL].