Answers to even numbered problems
HW #14:
- 4.126: F = 100 N; By = 364 N j; Ay = 236 N j
- 4.208: Ay = 280 lbs j; Ax = -160 lbs i; Ey = 200 lbs j; By = -140 lbs j;
Bx = -240 lbs i; Cy = -140 lbs j; Cx = 400 lbs i.
HW #15:
- 4.226: T1 = 1,680 N; T2 = 2000 N; R = 4610 N.
- 5.6: Ay = -480 N j; Fy = 4,480 N j; Fab = 800 N (T); Fag = 640 N
(C); Ffe = 4,530 N (C).
HW #16:
- 5.30: Gy = 1.73 kN; Gx = .650 kN; Fdf = Fbd = .997 kN
HW#17: No even numbered problems.
HW#18:
- 5.200: Th = 5.27 x 10^7 lbs; theta = 37.1 degrees
HW#19:
- 6.2a) Pmin = 35.3 N; b) Pmin = 39.2 N.
HW#20:
- 7.10: x = 1in, y = 2.98 in
- 7.26: x=z=0, y = 7/10 H
- 7.44: x = 0.894 in (using the axes marked on the diagram), y = 2.33
in.
- 7.104: x = -3/8 l, y = l/8, z = -l/4.
HW#21:
- 1.50: v = + or - (0.45 - 10/3 x^3 ) ^1/2
HW#22:
- 1.56: | a min| > or = 20 ft /s^2
- 1.80: y = -2x^3.
HW#23:
- 1.136: a) d/dt |v| = -20 m/s^2 b) en = .384
i + .512 j + .768 k
HW#24
- 2.12: alpha = 30
- 2.20: theta = 18
- 2.40: Pmax = 441N
- 2.52: |a min| = 8/15 g = 5.23
HW#25
HW#26
- 2.102: mu = .577
- 2.106: delta = .553 ft
HW#27
- 2.142 Here, let the boat itself be L long, so that the man starts
out at the very end of the boat. Use your knowledge of the location of
the center of mass for the man-boat system, and the relative positions of
the boat and man mass centers to get the answer. Also, use the end of
the pier as the origin of your coordinate system.
- 2.150: vbfy = 2.82 ft/s vafy = -2.35 ft/s
- 2.160: vbf = 31.2 ft/s up the plane; The block B will move a
total of 10.1 ft from its initial resting position.
HW#28
- 3.22: omega 2 = .205 rad/s k; omega 3 = -.473 rad/s
k and vs = 8.14 cm/s i
HW#29
- 3.58: omega2 = -2 k rad/s; alpha2 = 6 rad /s^2 k; omega3 = 0; alpha
3 = 6 rad/s^2 k
- 3.92: v(2s) = 7 m/s; v(5s) = 22 m/s
HW#30
- 3.120: alpha = 1.22 rad/s^2 k
- 3.122: omega(wheel) = .381 rad/s k; alpha(wheel) = -2.39 rad/s^2
k.
HW#31
HW#32
- 4.32: Ixx(c) = M(h^2/18 + t^2/12); Iyy(c) = M(b^2/18 + t^2/12)
; Izz(c) = Izz(p); Ixy(c) = -Mbh/36
- 4.52: Ixx(c) = .070MR^2 + mt^2/12
HW#33
- 4.62: xc = 5/14 g sin Beta t^2 + L
- 4.70: ac = mu g; alpha = 4 mu g /R
- 4.98: alpha = -10.17 rad/s^2 ccw; acyl = 3.39 ft/s^2 j; ablock = -3.39
ft/s^2 j
HW#34
- 4.118: a) Ff = 6.7 lbs to right and alpha = 6.7 rad/s^2 k b) mu >= .104
- 4.122: Normal(up) = 160 lbs, Normal(horiz) = 75.9 lbs, Friction = 16.0 lbs
HW#35
- 4.166: theta final = 1/2 (mu^2 + 1) R / (mu (mu + 1) g)