# Velocity versus Time Graph help?

1. Sep 13, 2014

### lkj6778

What does a vertical line graph pointing straight up mean? Same for down? What does a horizontal line mean?

y axis=velocity (m/s)

x axis=time (s)

Last edited: Sep 13, 2014
2. Sep 13, 2014

### Bandersnatch

Vertical line doesn't mean anything. It's not even a proper function. f(x) can have only one output per x.
It doesn't make sense intuitively either: one body cannot have simultaneously every possible velocity.

Horizontal means constancy.

3. Sep 13, 2014

### lkj6778

I was doing a lab with my group where we had to use a motion detector to match the target graphs given. And yes, my axes are correct. (University Physics 1)

4. Sep 13, 2014

### lkj6778

Velocity=(m/s)

Time=(s)

5. Sep 13, 2014

### Staff: Mentor

Bandersnatch is correct. A vertical line on a velocity time graph is nonsense. It means that the object has every velocity and only exists for an instant.

A horizontal line means a constant speed.

6. Sep 13, 2014

### sophiecentaur

It could help to add that a 'nearly vertical' line would represent a very rapid change of velocity - thus avoiding the problem of every velocity existing at once. 'Near as dammit', instant change of velocity - as when a ball bearing hits the front of a locomotive. The line is not quite vertical.

7. Sep 13, 2014

### HallsofIvy

Right- the ball bearing has just enough time to say "ouch"!