# Finding Velocity on a Position/Time Graph

Hey everyone, i'm having trouble finding velocity on a straight line position/time graph. Every single equation I do ends up with a different answer, which doesn't make sense because it's a straight line.

I know the equation is

Vf-Vi/Tf-ti

The answer to this question is 1.4m/s N

Example:

45-25/28-16= 1.666666m/s Wrong answer. I'm just taking these from the graph by the way.

Could someone please explain what i'm doing wrong? I'm calculating the slope which seems to change with every calculation that I do, which I understand is wrong.

Try to post the graph so we can see it. Also, if your v is velocity, you are dividing a velocity change by an elapsed time. That gives acceleration. If you want velocity, divide displacement by time.

SammyS
Staff Emeritus
Homework Helper
Gold Member
Hey everyone, i'm having trouble finding velocity on a straight line position/time graph. Every single equation I do ends up with a different answer, which doesn't make sense because it's a straight line.

I know the equation is

Vf-Vi/Tf-ti

The answer to this question is 1.4m/s N

Example:

45-25/28-16= 1.666666m/s Wrong answer. I'm just taking these from the graph by the way.