Question: Calculating Work with a Line Integral

In summary, the problem requires finding the work done by the force field F on a particle moving along the curve C, with given equations for F and C. To solve, the parametric equations for C must be determined, and then substituted into the integral formula for work done by a force field. The correct answer is 3/5.
  • #1
Breedlove
27
0

Homework Statement


Find the work doneby the force field F on a particle that moves along the curve C.
F(x,y)=xy i + x^2j
C: x=y^2 from (0,0) to (1,1)


Homework Equations



[tex]\int[/tex]F dot dr=[tex]\int^{b}_{a}F(r(t))dotr'(t)dt[/tex]

The Attempt at a Solution



Okay, so I parametrized x=t and y=t^2 (giving r(t)=ti+t^2j right?) and substituted those values in for x and y in F, dotted that with 1i+2tj because I think that it is the derivative of r, if the parametric equations for r are x=t and y=t^2. I then took the integral of the dot product i just took over the interval 0 to 1. I ended up with 3/4 but the correct answer is 3/5
 
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  • #2
Breedlove said:
Okay, so I parametrized x=t and y=t^2 (giving r(t)=ti+t^2j right?)
No, the curve is x=y^2 not y=x^2 so your parametric form of y should be [tex]y=\sqrt{t}[/tex]. Alternatively use: [tex]y=t[/tex] and [tex]x=t^2[/tex].
 

1. What is a line integral?

A line integral is a mathematical concept used in calculus to calculate the total value of a function along a curve or line. It is a generalization of the integral in one variable to higher dimensions.

2. How is a line integral different from a regular integral?

A regular integral involves finding the area under a curve in a two-dimensional plane. A line integral, on the other hand, involves finding the total value of a function along a curve in a higher dimensional space.

3. What is the purpose of using a line integral?

A line integral has various applications in physics, engineering, and mathematics. It can be used to calculate work done in a force field, electric field, or magnetic field. It also has applications in fluid mechanics, where it is used to calculate fluid flow along a curve.

4. How is a line integral calculated?

A line integral can be calculated by breaking down the curve into small segments and approximating the value of the function at each segment. Then, the values are summed up to get an approximation of the total value of the function along the curve. As the number of segments increases, the approximation becomes more accurate.

5. Can a line integral be negative?

Yes, a line integral can be negative. This occurs when the function being integrated has a negative value along the curve. It is important to pay attention to the direction of the curve when calculating a line integral, as it can affect the sign of the result.

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