How to Calculate the Area Under a Curve for v(t) Using Integration?

  • Thread starter brycenrg
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In summary: So how do you get that from the integral?In summary, to show the area under the curve of v(t) is equal to the displacement from t1 to t2, you can integrate v(t) = vt dt and find that the result is x(t2) - x(t1), which is the displacement at t1 and t2 respectively. This shows that the area under the curve is equal to the displacement between those two points.
  • #1
brycenrg
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Homework Statement


Show the area under the curve of v(t) is equal to the displacement from t1 to t2

Homework Equations


x/t = v

The Attempt at a Solution


Integrate V(t) = vt dt
(v/2)*t^2]t1 to t2
(v/2)*t1^2 - (v/2)*t2^2

Not sure if that is good enough or how toactually show it. To find the area you take the integration and v(t) is just the derivative of x(t) but I am not how to show it exactly.
 
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  • #2
I would do it like this:
##\int^{t1}_{t2} v(t)dt##
You basically have it.
 
  • #3
Thank you how do we write like that in this forum?
 
  • #5
brycenrg said:

Homework Statement


Show the area under the curve of v(t) is equal to the displacement from t1 to t2

Homework Equations


x/t = v
This equation isn't relevant if the velocity isn't constant.
brycenrg said:

The Attempt at a Solution


Integrate V(t) = vt dt
(v/2)*t^2]t1 to t2
(v/2)*t1^2 - (v/2)*t2^2

Not sure if that is good enough or how toactually show it. To find the area you take the integration and v(t) is just the derivative of x(t) but I am not how to show it exactly.
Since v(t) = ##\frac{dx}{dt}##, your integral is ##\int_{t_1}^{t_2}v(t) dt = \int_{t_1}^{t_2} \frac{dx}{dt} dt = \int_{t_1}^{t_2} dx##. If you carry that out, what do you get?
 
  • #6
thank you guys. You get t2-t1
 
  • #7
brycenrg said:
thank you guys. You get t2-t1
No. In the final integral in Mark's post, the limit variable and integration variable are different: ##\int_{t=t_1}^{t_2}dx##.
What is x when t=t1?
 
  • #8
Well isn't x = t1 when t is t1
I thought it was x]t2 upper t1 lower
So it's t2 - t1
 
  • #9
brycenrg said:
Well isn't x = t1 when t is t1
I thought it was x]t2 upper t1 lower
So it's t2 - t1
No. x is a position. What is the position at time t1? (so create one!)
 
  • #10
So I could say t1 = 1 and t2 = 2
So then it would be 1 in that case.
So the area would be 1 lol I dono
 
  • #11
brycenrg said:
So I could say t1 = 1 and t2 = 2
So then it would be 1 in that case.
So the area would be 1 lol I dono
No, you can't just plug in arbitrary numbers.
The question asks you to show that the area equals "the displacement from t1 to t2". If the displacement x is a function of t, x(t), how would you write the displacement at time t?
 
  • #12
X(t2) - x(t1) is that what they want?
 
  • #13
brycenrg said:
X(t2) - x(t1) is that what they want?
Yes.
 
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Related to How to Calculate the Area Under a Curve for v(t) Using Integration?

1. What is the purpose of showing the area under a curve?

The area under a curve represents the total value or quantity of a variable over a specific range. It is often used to analyze and compare data, as well as to understand the behavior and trends of a particular phenomenon.

2. How is the area under a curve calculated?

The area under a curve is calculated by dividing the curve into small, equal intervals and approximating the area of each interval using a geometric shape, such as rectangles or trapezoids. The sum of these approximated areas gives an estimate of the total area under the curve.

3. Why is it important to show the area under a curve?

Showing the area under a curve allows for a visual representation of the data, making it easier to understand and interpret. It also provides a more accurate measure of the total value or quantity of a variable compared to just looking at specific data points.

4. What types of curves can have an area under them?

Any continuous curve can have an area under it, including linear, polynomial, logarithmic, and exponential curves. However, discontinuous curves or curves with undefined values cannot have a meaningful area under them.

5. Can the area under a curve be negative?

Yes, the area under a curve can be negative if the curve dips below the x-axis. This indicates that the total value or quantity of the variable over the given range is decreasing or has a negative impact. However, the magnitude of the negative area is still important in understanding the behavior of the variable.

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