Creating a Position vs. Time Graph for a Moving Car

  • Thread starter Thread starter swede5670
  • Start date Start date
  • Tags Tags
    Graph Position
AI Thread Summary
To create a position versus time graph for a car moving towards an observer and accelerating, the graph should start at a point representing the car's initial position and curve upward, indicating increasing speed. A straight line would imply uniform motion, which contradicts the car's accelerating behavior. Some participants debated the appropriate placement of the origin, with suggestions that it should represent the car's position at time zero rather than the observer's. Labeling the axes and providing a title for the graph are also important for clarity. Overall, the graph should depict a curve that reflects the car's increasing speed as it approaches the observer.
swede5670
Messages
78
Reaction score
0

Homework Statement


A car is moving down the street toward you and speeding up. Create a corresponding position versus time graph.


Homework Equations


Well its just a graph so...none?


The Attempt at a Solution



I submitted a graph that started at the origin and had a curved, positive slope. For some reason that was called incorrect and I'm not sure how else the graph would look. It cannot be a straight line because that would imply that the object had uniform motion
 
Physics news on Phys.org
swede5670 said:

Homework Statement


A car is moving down the street toward you and speeding up. Create a corresponding position versus time graph.

Homework Equations


Well its just a graph so...none?

The Attempt at a Solution



I submitted a graph that started at the origin and had a curved, positive slope. For some reason that was called incorrect and I'm not sure how else the graph would look. It cannot be a straight line because that would imply that the object had uniform motion

What you describe is a diminishing position relationship. Perhaps the desired answer is one that starts slowly at the distance away the car is and describes a downward parabolic arc that ends at T = road kill?
 
How did you shape it? If it's curved like the letter 'J', I don't see what's wrong with that. But if it's shaped like the letter 'r', that means it decelerating.
Do you know for sure that the curve is wrong, or did you maybe label the axes incorrectly, or not put a title for the graph?
 
Wecht said:
How did you shape it? If it's curved like the letter 'J', I don't see what's wrong with that. But if it's shaped like the letter 'r', that means it decelerating.
Do you know for sure that the curve is wrong, or did you maybe label the axes incorrectly, or not put a title for the graph?

I didn't label anything. You should try and set up axes where the initial condition at T= 0 is the distance away. And goes to smaller distance faster the closer it gets to T = impact.
 
Hi swede5670! :smile:
swede5670 said:
A car is moving down the street toward you and speeding up. Create a corresponding position versus time graph.

I submitted a graph that started at the origin and had a curved, positive slope. For some reason that was called incorrect and I'm not sure how else the graph would look. It cannot be a straight line because that would imply that the object had uniform motion

Why the origin?

Isn't that where you are? :smile:
 
Hm I don't think so, TinyTim. The origin should be the car's position at t = 0. Since it's accelerating towards him, he can't be at the point where the car is, because then it wouldn't be accelerating towards him.
 
Wecht said:
Hm I don't think so, TinyTim. The origin should be the car's position at t = 0. Since it's accelerating towards him, he can't be at the point where the car is, because then it wouldn't be accelerating towards him.

Hi Wecht! :smile:

I think the origin should be the observer's position.

If the car was falling out of the sky, would the origin still be the car's position at t = 0? :wink:
 
I'm not sure I'm understanding you correctly. The question says the car is coming down the street towards you; I'm pretty sure it's safe to assume that it's not falling out of the sky.
 
From what I understood it should be something like ..mm the part of the circle at the I quadrant, or a ¯| curve.
 
Last edited:
  • #10
I think you guys are making this more complicated than it really is.
 
  • #11
Wait, is this supposed to be an x-position vs time graph of the car, or what?
 
  • #12
swede5670 said:
Create a corresponding position versus time graph.


Yup, its a X vs t graph
 
  • #13
So if it's an x vs t graph of the car, it doesn't matter where the person is. Why is TinyTim suggesting that the car is falling out of the sky? And also that the origin is the position of the person?
 
Back
Top