# Velocity versus time graph

1. Nov 1, 2006

### L²Cc

what does a vertical line in a velocity versus time graph imply?

2. Nov 1, 2006

Is you set the velocity axis to be horizontal, and the time axis to be vertical, then a vertical line implies constant velocity.

Else, it doesn't imply anything, since that set of points is not even a function.

3. Nov 1, 2006

### L²Cc

oops...should have given out that info. hmm..the velocity axis is horizontal, whereas time is vertical....in this situation, what does the vertical line imply?

Last edited: Nov 1, 2006
4. Nov 1, 2006

5. Nov 1, 2006

### L²Cc

oops, human error.

6. Nov 1, 2006

### ZapperZ

Staff Emeritus
The other thread has been deleted. Please note that it is explicitly mentioned in the PF Guidelines that everyone has agreed to that multiple posting is not allowed.

Zz.

7. Nov 1, 2006

### Integral

Staff Emeritus
Suppose the vertical part of the graph occurs at $x_0$.

What is the velocity at $x_0 - \delta$ ?

What is the velocity at $x_0 + \delta$ ?

Ok, now what has happened at the verical portion of the graph?

8. Nov 2, 2006

### ocalhoun

I suppose that could only happen if the velocity at that time was infinite, as otherwise the vertical line would have an upper limit to it.
It would also mean that the velocity of whatever you're measuring just jumped instantly with no time for acceleration, which would be highly unusual.

In other words, if I saw such a graph, the first things I would check would be the veracity of the data and the validity of the math.

9. Nov 4, 2006

### rcgldr

That something was wrong with the data or how the graph was plotted. As mentioned, maybe the axis got reversed (velocity is horiztonal, time is vertical).