Position-Time graph vs. Velocity-Time graph

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SUMMARY

The discussion focuses on the interpretation of position-time and velocity-time graphs, specifically analyzing a scenario with constant velocity and parabolic curves indicating acceleration. The constant velocity between position 0 and time 8.2 seconds is established at 1.5 m/s. Participants clarify how to represent the curves on the velocity-time graph, emphasizing that the curved sections indicate constant acceleration, resulting in a sloping v-t graph. The correct approach involves identifying straight sections and connecting them appropriately, particularly when transitioning from a speed decrease.

PREREQUISITES
  • Understanding of position-time and velocity-time graph concepts
  • Knowledge of basic kinematics, including acceleration and velocity
  • Ability to interpret graphical data and slopes
  • Familiarity with parabolic motion and its representation on graphs
NEXT STEPS
  • Study the principles of kinematics in physics
  • Learn how to derive velocity from position-time graphs
  • Explore the concept of acceleration and its graphical representation
  • Practice creating and interpreting velocity-time graphs from various motion scenarios
USEFUL FOR

Students in physics, educators teaching kinematics, and anyone interested in understanding motion through graphical analysis.

BloodyMinded
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The page layout is included in the picture attachments which are in order.
So far, if I'm correct, the constant velocity between position- 0 and time- 8.2 is 1.5m/s
The part I'm having trouble with is the curves of the line (how to figure them out and how to place them on the velocity-time graph).
What I've done for the curves is: 14-13/10-8.2 = .555 but I don't think that is right.
I would be most appreciative if you guys could help me out.
 

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BloodyMinded said:
The page layout is included in the picture attachments which are in order.
So far, if I'm correct, the constant velocity between position- 0 and time- 8.2 is 1.5m/s
The part I'm having trouble with is the curves of the line (how to figure them out and how to place them on the velocity-time graph).
What I've done for the curves is: 14-13/10-8.2 = .555 but I don't think that is right.
I would be most appreciative if you guys could help me out.

In the absence of any conflicting data, it is reasonable to a assume that the curved sections are parabolic - meaning constant acceleration - meaning the v-t graph will be sloping up or down at a constant rate.

I would usually identify the long straight sections of the v-t graph - you have the first one, the next one will last from 10 seconds to 18 seconds Then just join the ends of the straight sections [those sections will probably be disjoint] with straight lines. same for the last bit.
 
Okay, so I'm learning the same exact thing in my science class. In fact, we just had a test over it today! So, the first one is a position vs. time graph, right? Okay, so the line that you're having trouble with is more of a little "hump" like shape. The "hump" basically means that the speed of the elevator is decreasing a little.

So, you're trying to figure out how to place it on a velocity vs. time graph. Well, to show that you're slowing down on a velocity vs. time graph, you would abandon that small little diagonal line that you drew, and instead, make a straight line.

So, to put it simpler, you have your straight line, and then, make a vertical line going all the way down to 1 m/s.
*The reason you go down to 1 is because the slope of the line in the position vs. time graph is 1/1 or 1.
Then you move the line over 1 second.

(The next part kind of exceeds what your asking, but you could use it to check your work)

After that, you would go down to 0 on the horizontal axis from 10 seconds to 18 seconds. Then, since the slope of the last diagonal line is -1, you would go down (using a vertical line) to -1 on the x-axis and draw a horizontal line from 18 to 25 seconds.

Hope I helped you just a little. It took a while for me to type:)
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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