Evaluate the line integral \( \vec{F} = \langle -y/(x^2+y^2), x/(x^2+y^2) \rangle \)
over the curve \( \mathcal{C}: \langle \cos(t), \sin(t) \rangle; 0 \leq t \leq 2\pi \)

Evaluate the line integral \(\displaystyle{ \vec{F} = zx\hat{i} + zy\hat{j} + x\hat{k} }\)
\( \mathcal{C}: \langle \cos(t),\sin(t),t \rangle; 0 \leq t \leq \pi \)

Determine the work done by the conservative vector field \(\displaystyle{ \vec{F} = yz\hat{i} + xz\hat{j} + xy\hat{k} }\) along any smooth curve from \(A(0,0,0)\) to \(B(1,1,1)\).

Evaluate the line integral \( \vec{F} = \langle x^3, -z, 2xy \rangle \) over the curve \( \mathcal{C}: \langle t^2, \sqrt{t}, \sqrt{t} \rangle; 2 \leq t \leq 4 \)

Consider the force field \(\vec{F}(x,y) = \langle y^2-x^3, x^5 \rangle\) Newtons, where \(x\) and \(y\) are in meters. Let \(C_1\) be the oriented curve from \((0,0)\) to \((1,1)\), along the graph of \(y=x\). Let \(C_2\) be the oriented curve along \((0,0)\) to \((1,1)\), along the graph of \(y=x^2\). Calculate the work done by \(\vec{F}\) along \(C_1\) and \(C_2\) and show that they are not equal.

He has several mistakes when writing this problem.
1. He says the curves start at \((0,1)\) but they actually start at \((0,0)\). He works the problem as if they start at \((0,0)\).
2. His second integral should be \(\int{ F(\hat{r}(t)) \cdot \hat{r}’(t)~dt }\)
Here is the link to the blog entry for this problem: blog entry

Calculate the work done by the vector field \( \vec{F}(x,y) = xy\hat{i} + 3y^2\hat{j} \) along the path \(x=11t^4\), \(y=t^3\) by evaluating the integral \( W = \int_{\mathcal{C}}{ \vec{F} \cdot d\vec{r} } \) on \( 0 \leq t \leq 1 \).

45

The force exerted by an electric charge at the origin on a charged particle at the point \((x,y,z)\) with position vector \(\vec{r} = \langle x,y,z \rangle\) is \(\displaystyle{ \vec{F}(\vec{r}) = \frac{K\vec{r}}{|\vec{r}|^3}}\), where K is constant. Assume \(K=10\). Find the work done as the particle moves along a straight line from \((2,0,0)\) to \((2,2,3)\).

Calculate the work done by the vector field \(\vec{F}(x,y)=(x+y)\hat{i} + (y-x)\hat{j}\) along the path \(x=y^2\) from \((1,1)\) to \((4,2)\) by evaluating the integral \(W=\int_{\mathcal{C}}{ \vec{F} \cdot d\vec{r} }\).

Calculate the work done by the vector field \(\vec{F}(x,y)=(x+y)\hat{i} + (y-x)\hat{j}\) along the path \(x=2t^2+t+1\), \(y=1+t^2\) from \((1,1)\) to \((4,2)\) by evaluating the integral \(W=\int_{\mathcal{C}}{ \vec{F} \cdot d\vec{r} }\).

Calculate the work done by the vector field \( \vec{F}(x,y) = (x+y)\hat{i} + (y-x)\hat{j} \) along \(y=1\) from \((1,1)\) to \((4,1)\) then along \(x=4\) from \((4,1)\) to \((4,2)\) by evaluating the integral \( W = \int_{\mathcal{C}}{ \vec{F} \cdot d\vec{r} } \).

Evaluate the line integral \( \int_{\mathcal{C}}{ xy~dx+y~dy } \) along the curve \( \mathcal{C}: \vec{r}(t)=2t\vec{i} +10t\vec{j}; 0 \leq t \leq 1 \)

\(\displaystyle{\frac{190}{3}}\)

Evaluate the line integral \( \int_{\mathcal{C}}{ (2x-y)~dx+(x+3y)~dy } \)
\( \mathcal{C}: \) along the x-axis from 0 to 5

To parameterize the curve, we let \(x=t\) which gives us the interval \(0\leq t\leq 5\). The y-value is just zero since the line is along the x-axis. So we have \(\vec{r}(t)=t\vec{i}+0\vec{j}\)

25

Evaluate the line integral \( \int_{\mathcal{C}}{ 9x~dy-9y~dx }\) along the curve \( \mathcal{C}: \langle 3\cos(t), 2\sin(t) \rangle; 0 \leq t \leq \pi \)

Evaluate the line integral \( \int_{\mathcal{C}}{(2x+yz)dx +xz dy + xy dz} \) along the curve \( \mathcal{C}: \) straight line \( (0,0,0) \) to \( (1,2,-1) \)

Compute \(\displaystyle{ \int_{(1,1)}^{(4,2)}{ (x+y)dx+(y-x)dy } }\) along the curve \(x=y^2\).