418 Appendix
(b) W
max
= 1669.4220 at t = 0.331667 and t = 0.995000.
(c) α
max
= 0.201447 at t = 0.405759
(d) t = 0.663333 s
6.10. (a)
¨
ψ =
2
˙
θ
cos θ
+
˙
ψ sin θ
¨
θ =−
1
5
˙
ψ
2
sin θ cos θ −
6
5
˙
ψcos θ + 16 sin θ
˙
=
2
3
˙
ψ
˙
θ cos θ
(b) t = 0
ψ = 0 θ =
π
6
= 0.523599 φ = 0 X = 0
˙
ψ = 4
˙
θ = 0 = 2 Y = 0
t = 1
ψ = 2.891062 θ = 0.096692 φ = 2.754937 X = 0.156089
˙
ψ = 1.726344
˙
θ =−0.678622 = 1.294624 Y =−0.919876
t = 1.5
ψ = 3.480268 θ =−0.595660 φ = 3.225671 X =−0.071231
˙
ψ = 0.534888
˙
θ =−2.748494 = 0.831908 Y =−0.910777
t = 2.0
ψ =−3.157916 θ =−0.517934 φ = 10.294732 X =−0.436413
˙
ψ = 0.633105
˙
θ = 2.483279 = 0.857619 Y =−0.856059
t = 2.5
ψ =−2.533888 θ = 0.116376 φ = 10.793919 X =−0.666352
˙
ψ = 1.785449
˙
θ = 0.645929 = 1.317532 Y =−0.784324
t = 3.0
ψ =−1.375078 θ = 0.380226 φ = 11.849700 X =−0.844784
˙
ψ = 2.927582
˙
θ = 0.476119 = 1.706236 Y =−0.328526
t = 3.5
ψ = 0.423844 θ = 0.522848 φ = 13.623335 X =−0.168626
˙
ψ = 3.993075
˙
θ =−0.050408 = 1.998268 Y = 0.013511
θ
min
=−1.542703 rad (−88.39
◦
)att = 1.735130 s
θ
max
=
π
6
at t = 0 and t = 3.470260 s when
˙
ψ,
˙
θ, and also
return to their initial values.
θ = 0att = 1.125585 s and 2.344675 s.