Finding the greatest distance from the origin given a velocity vs. time graph.

[1irishman]

Homework Statement

If given a velocity vs. time graph where max. constant velocity is 2m/s for 2s and the object turns around at 4s with max negative constant velocity is -2m/s for 2s. How do i find the greatest distance from the origin?

Homework Equations

d= vi+vf/2 *t
d=vit + 1/2at^2

The Attempt at a Solution

i'm really not sure what to do here...please hints?

 

[Delphi51]

Okay, so you have constant speed for the first two seconds and the distance increases steadily at d = vt. Then the direction reverses and the distance diminishes to zero over the next 2 seconds. The greatest distance is pretty clear . . .

 

[1irishman]

is it 5m?

 

[1irishman]

is there a formula to help figure this out from just looking at a v-t graph coordinates?

 

[Delphi51]

Terribly sorry, I didn't see the bit about "turning around at 4s". Now I don't understand it because there is no indication of what happens between 2 and 4 seconds.

If you are looking at the graph, I suggest you find the distance traveled up to the turnaround time of 4 seconds. The area under the graph is the distance. Or use d = vt for the first 2 seconds and whatever is appropriate for the next two.