Unraveling the Mystery of Non-45 Degree Slopes

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Discussion Overview

The discussion revolves around the interpretation of mathematical relationships in physics, particularly focusing on the equations for potential energy in springs and the kinematic equation for motion. Participants explore the implications of varying spring constants and their effects on graphical representations, specifically addressing the area under the curve in relation to different slopes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants note that equations like v = 0.5at^2 and PE(spring)=0.5kx^2 typically assume a 45-degree slope for simplicity in understanding the area under the graph.
  • One participant questions the validity of using x^2 as the area when the spring constant k varies significantly, suggesting that the relationship may not hold if the slope is not 45 degrees.
  • Another participant expresses confusion about the original question and seeks clarification on the meaning of the slope being a 45-degree angle.
  • A participant later states that they resolved their confusion by recognizing that the potential energy can be expressed as PE = 0.5 k(x) times x, which helped them understand the x^2 term.
  • One participant elaborates that while the slope can vary (e.g., being 60 degrees or less than 45 degrees), the area under the curve remains consistent as 1/2kx^2, regardless of the value of k.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and confusion regarding the relationship between slope, spring constant, and area under the curve. There is no consensus on the implications of non-45-degree slopes, and multiple viewpoints regarding the interpretation of these relationships remain present.

Contextual Notes

Some participants reference calculus concepts, indicating that the discussion may depend on familiarity with differential and integral calculus, which could influence the understanding of the relationships discussed.

JFS321
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Hi all,

I notice the patterns such as v = 0.5at^2 and PE(spring)=0.5kx^2, etc...but, all examples I have seen show the slope (acceleration, or the spring constant, k) as being a 45 degree angle. Thus, the area of the triangle underneath the graph makes good sense (x^2 or t^2).

But, let's say we have an example where the spring constant is much larger or much smaller. Why is x^2 still valid as the base x height, if the two are not equal values?
 
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Maybe I'm just tired, but I'm really confused about your question. So that people don't start answering every question except what you meant, would you mind clarifying? (also, x, not v in your first one)
What do you mean a or k is a 45 degree angle?
I'm guessing that the answer you are looking for is going involve integration. What level of math are you comfortable with?
 
Sorry for the confusion. I'm evidently tired too.

I have it answered. All it took was writing PE = 0.5 k(x) times x. I couldn't intuitively see the x^2 mentally.
 
JFS321 said:
Hi all,

I notice the patterns such as v = 0.5at^2 and PE(spring)=0.5kx^2, etc...but, all examples I have seen show the slope (acceleration, or the spring constant, k) as being a 45 degree angle. Thus, the area of the triangle underneath the graph makes good sense (x^2 or t^2).

But, let's say we have an example where the spring constant is much larger or much smaller. Why is x^2 still valid as the base x height, if the two are not equal values?

Those terms come from calculus derivations. Are you familiar yet with differential and integral calculus?
 
JFS321 said:
Hi all,

I notice the patterns such as v = 0.5at^2
that is s = 1/2at^2
(and PE(spring)=0.5kx^2, etc...but, all examples I have seen show the slope (acceleration, or the spring constant, k) as being a 45 degree angle.
when you plot v vs.t, and the acceleration is constant, then you have a linear equation v = at, and the slope of the line is the acceleration. Thus, the area of the triangle underneath the graph is 1/2 at^2. Or since F=kx, the slope of the line is k. and the PE is 1/2kx^2. But the slope is not always 45 degress, it could be much higher , say 60 degrees , but the area under the curve (straight line) is still the same, the area of the triangle.
But, let's say we have an example where the spring constant is much larger or much smaller. Why is x^2 still valid as the base x height, if the two are not equal values?
Tey don't have to be equal. The area of the triangle is still 1/2kx^2 for the spring PE case, whether k is 1 (straight line graph for f = kx, k=1, 45 degree slope, or k is greater than 1 (higher slope and thus greater angle) or less than 1, (less steep slope , angle less than 45 degrees).
 

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