Can a position vs time graph be perfectly horizontal or vertical?

[caseyd1981]

I know this is going to sound easy, but I cannot find the answer anywhere..

We had a quiz today in my physics class, and one of the questions was a True/False question that stated that it is impossible for a position vs time graph of some animal to be perfectly vertical or perfectly horizontal.

We had just been told in our lecture that the velocity on a velocity vs time graph could not be vertical and I was tempted to answer True. But...could a position vs time graph of an object not be perfectly horizontal if the object was just standing still?

I answered False...

 

[kuruman]

I would agree that the position vs. time graph for an animal can be perfectly horizontal if the animal is standing still especially if the animal is road kill.

What do you think a perfectly vertical line implies? Can that happen for an animal?

 

[caseyd1981]

Great! I hope I got it right then...I have no clue what a vertical line would imply? Is there such a thing? It seems to me that the object would have to be in 2 positions at the same time, which is impossible.

And thanks for your help!

 

[kuruman]

...I have no clue what a vertical line would imply? Is there such a thing? It seems to me that the object would have to be in 2 positions at the same time, which is impossible.

More correctly, it means that the object would have to be in infinitely many positions at the same time, not just 2. The point of this question is to help you realize that the slope of the x vs t plot is the velocity of the object. "Horizontal" means zero slope, therefore zero velocity. "Vertical" means infinite slope, therefore infinite velocity.