Errors in Aug 2010 version of Ruina/Pratap
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Make money if you are the first to find an error: $1.00 for math errors,$5 for real errors or things that need deep fixing (with suggestion about how to fix). How?: Subject line in email: TEXT ERRORS. Then list like the Known Errors below, (XX are your initials), e.g.,

Sect 13.2, pg 642, paragraph above "More about pendula". -XX 2/5/09
In the argument of the exponentials change    gt/l     to     +- sqrt(g/l)t.

Known Errors
We keep track of typos, case and tense mismatches, mising closing parentheses, spelling and grammatical errors, etc, but don't list them all here. The errors below are more serious.

* = an appropriate repair has already been made in the source file
! = non-trivial error, readers should note.

## Errors

! Section 2.1, page 45, 1st equation: -IV 8/25/10
rB/A = -rB/A     should be     rB/A = -rA/B

! Section 2.3, page 68, item 7: -BE 8/26/10
As written there is a vector minus a scalar. Bad. The second term inside the absolute value sign needs to be multiplied by         rB/A / |rB/A|. That is, as written the second term is the length of the projection along the line. That needs to be multiplied by a unit vector along the line to make a vector to subtract from   rC/A.

! Section 2.3, page 69, paragraph over the first "Example" - CO 8/29/10
Change      AxB = (A1B2 - B2A1)e3   (As incorrectly printed, the cross product is zero.)
to      AxB = (A1B2 - A2B1)e3.

! Section 2.3, Sample 2.19, page 77: -SC 9/13/10
Change            A(-1,4)      to      A(-1,1)

! Section 2.4, pg 88, Moment about an axis example, - SC 9/18/10
Change            -17/sqrt(2) mN         to        -41/sqrt(2) mN

! Problem 2.7.11b, page 146. - EE 9/06/10
The cutout circle is not drawn to scale, it actually encompasses the center of the big circular plate.

! Problem 4.5.10, page 252 -KS 9/8/10
change           IE          to        CE
change    I,C and B     to     C and B

! Pages 285-6, truss matrices setup. -Dan Levine 10/31/10
There are a few errors in the matrix setup which are corrected here.

! Problem 5.2.7, page 314, -JZ 9/17/10
On the figure change the base lengthAF from        2L       to        3L.
(as printed, points C and D coincide)

! Problem 5.3.6, page 315, -AR 9/20/10
On the figure there should be rollers at E (and the figure should be bigger).

Sect. 6.3, pg. 357, "Pulley and Chain Drives" bottom of par. 1. -KL10/08/10
Change    "Fig 6.53B"    to    "Fig 6.55B"

! Problem 6.2.8, page 368 -AR 9/17/10
Delete the problem. The problem is not well enough defined. No simple fix.

Problem 6.3.2, page 371 -SP 10/13/10
dimension of bottom length is \ell (script letter L)

*Problem 6.3.14, page 373 -AR 10/13/10
Figure needs various clarifications.

! Problem 8.1.3, pg 409 (& 1007), Answer -NAS 10/17/10
Change     5.85 x 10^5N     to      5.85x10^4N.

! Sample 14.32, page 826. -MC 2007
Here is an extensive correction to this sample by Mike Coleman.
Also   v_D    should be    v_0.
and     v_P    should be    v_G.
First and second figures need A' (not A) on disk.

## Editorial suggestions

Section 16.1, Sample 16.8. Some ideas from Les Schaffer.
Do the frictionless case of Sample 16.8 in the text.
Point out that the increase in kinetic energy is the work of the contact force.
In the sample, use a dot product with e_r + mu e_theta to get the equation of motion in one less step. In the sample point out that the work of the constraint force is the change of kinetic energy.