Using the definitions in Eqs. l. 1 and 1.4, and appropriate diagrams, show that the dot product and cross product are distributive,(a) When the three
Is the cross product associative? (A x B) x C = A x (B x C).If so, prove it; if not, provide a counterexample.
Find the angle between the body diagonals of a cube.
Use the cross product to find the components of the unit vector n perpendicular to the plane shown in Fig. 1.11.
Prove the BAC-CAB role by writing out both sides in component form.
Prove that [A x (B x C)] + [B x (C x A)] + [C x (A x B)] = 0. Under what conditions does A x (B x C) = (A x B) x C?
Find the separation vector π from the source point (2, 8, 7) to the field point (4, 6, 8). Determine its magnitude (π), and construct the unit
(a) Prove that the two-dimensional rotation matrix (1.29) preserves dot products. (That is, show that Ay By + A z B z = Ay By + A z B z.)(b) What
Find the transformation matrix R that describes a rotation by 120o about an axis from the origin through the point (1, 1, 1). The rotation is
(a) How do the components of a vector transform under a translation of coordinates (x = x, y = y ?? a, z = z, Fig. 1.16a)?
(b) How do the components
Find the gradients of the following functions:(a) f(x, y, z) = x2 + y3 + z4.(b) f(x, y, z) = x2y3z4.(c) f(x, y, z) = ex sin(y) ln (z).
The height of a certain hill (in feet) is given by h(x, y) = 10(2xy – 3x2 – 4y2 – 18x + 28y + 12), where y is the distance (in miles) north, x
Let π, be the separation vector from a fixed point (x', y’, z') to the point (x, y, z), and let π be its length. Show that(a) ∆ (π2) = 2 π(b)
Suppose that f is a function of two variables (y and z) only. Show that the gradient ∆ f = (∂f/∂y)y + (∂f/∂z)z transforms as a vector under
Calculate the divergence of the following vector functions:(a) va = x2 x + 3xz 2 y – 2xz z.(b) vb = xy x + 2yz y + 3zx z.(c) vc = y2x + (2xy + z2)y
Sketch the vector function v = r/r2, and compute its divergence. The answer may surprise you... can you explain it?
In two dimensions, show that the divergence transforms as a scalar under rotations.
Calculate the cuds of the vector functions in Prob. 1.15.
Construct a vector function that has zero divergence and zero cud everywhere. (A constant will do the job, of course, but make it something a little
Prove product rules (i), (iv), and (v).
(a) If A and B are two vector functions, what does the expression (A ∙ ∆)B mean? (That is, what are its x, y, and z components in terms of the
(For masochists only.) Prove product rules (ii) and (vi). Refer to Prob. 1.21 for the definition of (A ∙ ∆)B.
Derive the three quotient rules.
(a) Check product rule (iv) (by calculating each term separately) for the functionsA = x x + 2 y y + 3z z; B = 3y x – 2xy.(b) Do the same for
Calculate the Laplacian of the following functions:(a) Ta= x2 + 2xy + 3z + 4.(b) Tb = sin x siny sin z.(c) Tc = e–5x sin 4 y cos 3z.(d) v = x2 x +
Prove that the divergence of a cud is always zero. Check it for function va in Prob. 1.15.
Prove that the curl of a gradient is always zero. Check it for function (b) in Prob. 1.11.
Calculate the line integral of the function v = x2x + 2yz y + y2 z from the origin to the point (1, 1, 1) by three different routes:(a) (0, 0, 0) →
Calculate the surface integral of the function in Ex. 1.7, over the bottom of the box. For consistency, let "upward" be the positive direction. Does
Calculate the volume integral of the function T = z2 over the tetrahedron with comers at (0,0,0), (1,0,0), (0,1,0), and (0,0,1).
Check the fundamental theorem for gradients, using T = x2 + 4xy + 2yz3, the points a = (0, 0, 0), b = (1, 1, 1), and the three paths in Fig.
Test the divergence theorem for the function v = (xy) x + (2yz) y + (3zx) z. Take as your volume the cube shown in Fig. 1.30, with sides of length 2.
Test Stokes' theorem for the function v = (xy) x + (2yz) y + (3zx) z, using the triangular shaded area of Fig. 1.34.
Check Corollary I by using the same function and boundary line as in Ex. 1.11, but integrating over the five sides of the cube in Fig. 1.35. The back
Find formulas for r, θ, Ф in terms of x, y, z (the inverse, in other words, of Eq. 1.62 ).
Express the unit vectors r, θ, Ф in terms of x, y, z (that is, derive Eq. 1.64). Check your answers several ways (r ∙ r = 1, θ ∙ Ф = r x θ =
(a) Check the divergence theorem for the function v1 = r2r, using as your volume the sphere of radius R, centered at the origin.(b) Do the same for
Compute the divergence of the function v = (r cos θ)r + (r sin θ) θ + (r sin θ cos Ф) Ф. Check the divergence theorem for this function, using
Compute the gradient and Laplacian of the function T = r (cos θ + sin θ cos Ф). Check the Laplacian by converting T to Cartesian coordinates and
Express the cylindrical unit vectors s, Ф, z in terms of x, y, z (that is, derive Eq. 1.75). "Invert" your formulas to get x, y, z. in terms of s,
(a) Find the divergence of the function v = s(2 + sin2 Ф)s + s sin Ф cos Ф Ф + 3z z.
(b) Test the divergence theorem for this function, using the
Evaluate the following integrals:(a) f62(3x2 – 2x – 1) δ (x – 3)dx.(b) f50 cos x δ (x – π) dx.(c) f30 x3 δ (x + 1) dx.(d) f∞-∞ ln(x +
Evaluate the following integrals:(a) f2_2(2x + 3) δ (3x) dx.(b) f02(x3 + 3x + 2) δ (1 – x)dx.(c) f1– l 9x2 δ (3x + 1)dx.(d) fa_∞ δ (x –
(a) Write an expression for the electric charge density p (r) of a point charge q at r'. Make sure that the volume integral of p equals q.(b) What is
Evaluate the following integrals:(a) f all space (r2 + r ∙ a + a2) δ3 (r – a) dτ, where a is a fixed vector and a is its magnitude.(b) fv | r
Evaluate the integral (where v is a sphere of radius R, centered at the origin) by two different methods, as in Ex.1.16.
(a) Let F1 = x2 z and F2 = x x + y y + z z. Calculate the divergence and curl of F1 and F2. Which one can be written as the gradient of a scalar?
For Theorem I show that (d) → (a), (a) → (c), (c) → (b), (b) → (c), and (c) → (a).
For Theorem 2 show that(d) → (a),(a) → (c),(c) → (b),(b) → (c), and (c) → (a).
(a) Which of the vectors in Problem 1.15 can be expressed as the gradient of a scalar? Find a scalar function that does the job.(b) Which can be
Check the divergence theorem for the function v = r2 cos ? r + r2 cos ? ? ? r2 cos ? sin ? ?, using as your volume one octant of the sphere of radius
Check Stokes' theorem using the function v = ay x + bx y (a and b are ,constants) and the circular path of radius R, centered at the origin in the xy
Compute the line integral of v = 6x + yz2y + (3y + z)z along the triangular path shown in Fig. 1.49. Check your answer using Stokes' theorem.
Compute the line integral of v = (r cos2 θ) r ?? (r cos θ sin θ) θ + 3r Ф around the path shown in Fig. 1.50 (the points are labeled by their
Check Stokes' theorem for the function v = yz, using the triangular surface shown in Fig.1.51.
Check the divergence theorem for the function v = r2 sin θ r + 4r2 cos θ = r2 tan θФ. using the volume of the "ice-cream cone" shown in Fig. 1.52
Here are two cute checks of the fundamental theorems:(a) Combine Corollary 2 to the gradient theorem with Stokes' theorem (v = ∆T, in this case).
Although the gradient, divergence, and cud theorems are the fundamental integral theorems of vector calculus, it is possible to derive a number of
The Integral is sometimes called the vector area of the surface S. If S happens to be flat, then |a| is the ordinay (scalar) area, obviously.(a) Find
(a) Find the divergence of the function v = r/r. First compute it directly, as in Eq. 1.84. Test your result using the divergence theorem, as in Eq.
(a) Twelve equal charges, q, are situated at the corners of a regular 12-sided polygon (for instance, one on each numeral of a clock face). What is
(a) Find the electric field (magnitude and direction) a distance z above the midpoint between two equal charges, q, a distance d apart (Fig. 2.4).
Find the electric field a distance z above one end of a straight line segment of length L (Fig. 2.7), which carries a uniform line charge λ. Check
Find the electric field a distance z above the center of a square loop (side a) carrying uniform line charge λ (Fig. 2.8).
Find the electric field a distance z above the center of a circular loop of radius r (Fig. 2.9), which carries a uniform line charge λ.
Find the electric field a distance z above the center of a flat circular disk of radius R (Fig. 2.10), which cames a uniform surface charge ??. What
Find the electric field a distance z from the center of a spherical surface of radius R (Fig. 2.11), which cames a uniform charge density a. Treat
Use your result in Prob. 2.7 to find the field inside and outside a sphere of radius R, which carries a uniform volume charge density p. Express your
Suppose the electric field in some region is found to be E = kr3r, in spherical coordinates (k is some constant).(a) Find the charge density p.(b)
A charge q sits at the back comer of a cube, as shown in Fig. 2.17. What is the flux of E through the shaded side?
Use Gauss's law to find the electric field inside and outside a spherical shell of radius R, which carries a uniform surface charge density a.
Use Gauss's law to find the electric field inside a uniformly charged sphere (charge density p). Compare your answer to Prob. 2.8.
Find the electric field a distance s from an infinitely long straight wire, which carries a uniform line charge λ. Compare Eq. 2.9.
Find the electric field inside a sphere which carries a charge density proportional to the distance from the origin, p = kr, for some constant k.
Problem 2.15 A hollow spherical shell carries charge density p = k/r2 in the region a b. Plot |E| as a function of r.
A long coaxial cable (Fig. 2.26) carries a uniform volume charge density p on the inner cylinder (radius a), and a uniform surface charge density on
An infinite plane slab, of thickness 2d, cames a uniform volume charge density p (Fig. 2.27). Find the electric field, as a function of y, where y =
Two spheres, each of radius R and carrying uniform charge densities + p and ? p, respectively, are placed so that they partially overlap (Fig. 2.28).
Calculate âˆ† x E directly from Eq. 2.8, by the method of Sect. 2.2.2. Refer to Prob. 1.62 if you get stuck.
One of these is an impossible electrostatic field. Which one?Here k is a constant with the appropriate units. For the possible one, find the
Find the potential inside and outside a uniformly charged solid sphere whose radius is R and whose total charge is q. Use infinity as your reference
Find the potential a distance s from an infinitely long straight wire that carries a uniform line charge λ. Compute the gradient of your potential,
For the charge configuration of Prob. 2.15, find the potential at the center, using infinity as your reference point.
For the configuration of Prob. 2.16, find the potential difference between a point on the axis and a point on the outer cylinder. Note that it is not
Using Eqs. 2.27 and 2.30, find the potential at a distance z above the center of the charge distributions in Fig. 2.34. In each case, compute E =
A conical surface (an empty ice-cream cone) carries a uniform surface charge σ. The height of the cone is h, as is the radius of the top. Find the
Find the potential on the axis of a uniformly charged solid cylinder, a distance z from the center. The length of the cylinder is L, its radius is R,
Use Eq. 2.29 to calculate the potential inside a uniformly charged solid sphere of radius R and total charge q. Compare your answer to Prob. 2.21.
Check that Eq. 2.29 satisfies Poisson's eqqation, by applying the Laplacian and using Eq. 1.102.
(a) Check that the results of Exs. 2.4 and 2.5, and Prob. 2.11, are consistent with Eq. 2.33.(b) Use Gauss's law to find the field inside and outside
(a) Three charges are situated at the corners of a square (side a), as shown in Fig. 2.41. How much work does it take to bring in another charge, +
Find the energy stored in a uniformly charged solid sphere of radius R and charge q. Do it three different ways: (a) Use Eq. 2.43. You found the
Here is a fourth way of computing the energy of a uniformly charged sphere: Assemble the sphere layer by layer, each time bringing in an
Consider two concentric spherical shells, of radii a and b. Suppose the inner one carries a charge q, and the outer one a charge – q (both of them
A metal sphere of radius R, carrying charge q, is surrounded by a thick concentric metal shell (inner radius a, outer radius b, as in Fig. 2.48). The
Two spherical cavities, of radii a and b, are hollowed out from the interior of a (neutral) conducting sphere of radius R (Fig. 2.49). At the center
Two large metal plates (each of area A) are held a distance d apart. Suppose we put a charge Q on each plate; what is the electrostatic pressure on
A metal sphere of radius R carries a total,charge Q. What is the force of repulsion between the "northern" hemisphere and the "southern" hemisphere?
Find the capacitance per unit length of two coaxial metal cylindrical tubes, of radii a and b (Fig.2.53).
Suppose the plates of a parallel-plate capacitor move closer together by an infinitesimal distance 6, as a result of their mutual attraction.(a) Use
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