to accompany
ORBITAL MECHANICS FOR ENGINEERING STUDENTS
Howard D. Curtis
Embry-Riddle Aeronautical University
Daytona Beach, Florida
, Solutions Manual Orbital Mechanics for Engineering Students Chapter 1
Problem 1.1
(a)
A A Ax iˆ Ay ˆj Azkˆ Axiˆ Ayˆj Azkˆ
Axiˆ Axiˆ Ayˆj Azkˆ Ayˆj Axiˆ Ayˆj Azkˆ Azkˆ Axiˆ Ayˆj Azkˆ
Ax2 iˆ iˆ Ax Ay iˆ ˆj Ax Az iˆ kˆ Ay Ax ˆj iˆ Ay2 ˆj ˆj Ay Az ˆj kˆ
AzAx kˆ iˆ AzAy kˆ ˆj Az2 kˆ kˆ
Ax2 1 Ax Ay 0 Ax Az 0 Ay Ax 0 Ay2 1 Ay Az 0 Az Ax 0 Az Ay 0 Az2 1
Ax2 Ay2 Az2
But, according to the Pythagorean Theorem, A 2x A y2 A z2 A2 , where A A , the magnitude of
the vector A . Thus A A A2 .
(b)
iˆ ˆj kˆ
A B C A Bx By Bz
Cx Cy Cz
Ax iˆ Ay ˆj Azkˆ iˆ ByCz BzCy ˆj BxCz BzCx kˆ BxCy ByCx
Ax ByCz BzCy Ay BxCz BzCx Az BxCy ByCx
or
A B C AxByCz AyBzCx AzBxCy AxBzCy AyBxCz AzByCx (1)
Note that A B C C A B , and according to (1)
C A B CxAyBz Cy AzBx Cz AxBy CxAzBy Cy AxBz Cz AyBx (2)
The right hand sides of (1) and (2) are identical. Hence A B C A B C .
(c)
iˆ ˆj kˆ iˆ ˆj kˆ
A B C Axiˆ Ayˆj Azkˆ Bx By Bz Ax Ay Az
Cx Cy Cz ByCz BzCy BzCx BxCy BxCy ByCx
Ay BxCy ByCx Az BzCx BxCz iˆ Az ByCz BzCy Ax BxCy ByCx ˆj
A B C B C A B C B C kˆ
x z x x z y y z z y
AyBxCy AzBxCz AyByCx AzBzCx iˆ AxByCx AzByCz AxBxCy AzBzCy ˆj
x z x y z y x x z y y z
A B C A B C A B C A B C kˆ
Bx AyCy AzCz Cx AyBy AzBz iˆ By AxCx AzCz Cy AxBx AzBz ˆj
z x x y y z x x y y
B A C A C C A B A B kˆ
Add and subtract the underlined terms to get
1
, Solutions Manual Orbital Mechanics for Engineering Students Chapter 1
A B C Bx AyCy AzCz AxCx Cx AyBy AzBz AxBx iˆ
By AxCx AzCz AyCy Cy AxBx AzBz AyBy ˆj
y y z z z x x
B A C A C A C C A B A B A B kˆ
z x x y y
z z
Bx iˆ By ˆj Bzkˆ A C A C A C C iˆ C ˆj C kˆ A B A B
x x y y z z x y z x x y y AzBz
or
A B C BA C CA B
Problem 1.2 Using the interchange of Dot and Cross we get
A B C D A B C D
But
A B C D C A B D (1)
Using the bac – cab rule on the right, yields
A B C D AC B BC A D
or
A B C D A DC B B DC A (2)
Substituting (2) into (1) we get
A B C D A CB D A DB C
Problem 1.3
Velocity analysis
From Equation 1.38,
v vo rrel vrel . (1)
From the given information we have
vo 10Iˆ 30Jˆ 5 0K̂ (2)
rrel r ro 150Iˆ 200Jˆ 300K̂ 300Iˆ 200Jˆ 100K̂ 150Iˆ 400Jˆ 200K̂ (3)
Iˆ Jˆ K̂
rrel 0.6 0.4 1.0 320Iˆ 270Jˆ 300K̂ (4)
150 400 200
2