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Thomas Calculus 13th [Solutions]

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960 Chapter 13 Vector-Valued Functions and Motion in Space<br />

5. 2t 2 0, r 2cos 4t r 8sin 4t r 32cos 4t<br />

v 8sin 4t ur<br />

2cos 4 t (2) u 8 sin 4t ur<br />

4 cos 4t<br />

u<br />

2<br />

a 32cos 4t 2cos 4 t (2) ur<br />

2cos 4t 0 2 8sin 4 t (2) u<br />

32cos 4t 8cos 4t ur<br />

0 32sin 4t u 40 cos 4t ur<br />

32 sin 4t<br />

u<br />

6.<br />

2<br />

0 0<br />

r v 2 GM ( e 1) GM ( e 1)<br />

e 1 v0 v0<br />

;<br />

GM r r<br />

Circle: e<br />

0 v GM<br />

0 r<br />

0 0<br />

Ellipse: 0 e 1 GM v 2GM<br />

r 0 r<br />

0<br />

0 0<br />

Parabola: e 1 v 2GM<br />

0 r0<br />

Hyperbola: e 1 v 2GM<br />

0 r<br />

0<br />

7. r GM v 2 GM GM<br />

2<br />

v<br />

r<br />

v r<br />

which is constant since G, M, and r (the radius of orbit) are constant<br />

8.<br />

1 1 ( ) 1 ( ) ( ) ( ) 1 ( ) ( )<br />

( ) ( ) A r t t r t t r t r t r t t r t<br />

A r t t r t r( t) r( t) r( t) 1 r( t) r( t)<br />

2 t 2 t 2 t 2 t t<br />

1 r( t t) r( t) 1 ( ) ( )<br />

( ) dA<br />

r t t r t<br />

lim ( ) 1 d r<br />

( ) 1 d r<br />

r t r t r t r( t)<br />

1 r r<br />

2 t dt<br />

t 0<br />

2 t 2 dt 2 dt 2<br />

9.<br />

2 2 4 2 4<br />

2 2<br />

2 2 2 4 2 4<br />

r0 v0<br />

T a 1 e T a 1 e a 1 1 (from Equation 5)<br />

r v<br />

GM<br />

2 2 2 2<br />

0 0 r0 v0 r0 v0<br />

2 4 2 2 2 4<br />

2 4 2<br />

2 4 2 4 0 0<br />

2<br />

0 0 0 0 2 4 a 2GM r v<br />

a r v r v 0 0 0 0 2 4 2 0 0<br />

2 a GMr v r v GM r v<br />

4 a<br />

2 2 2 2 2 2 2 2 2 2<br />

2<br />

0 0 0 0 0<br />

0<br />

4 4 2<br />

r v G M GM r v G M r G M<br />

r GM GM<br />

2 4<br />

4 a 1 2<br />

2a<br />

GM<br />

(from Equation 10)<br />

2 3 2 2<br />

2<br />

T 4 a T 4<br />

GM 3<br />

a GM<br />

10. For each of the planets listed we form the ratio<br />

2 3<br />

T / a<br />

.<br />

2<br />

(4 ) / ( GM )<br />

The values we obtain are<br />

Mercury 1.00225<br />

Venus 1.00288<br />

Mars 1.00252<br />

Saturn 1.00019<br />

These values are all close to 1, so they support Keplers third law.<br />

11. Solve Keplers third law for a and double this result:<br />

12. Solve Keplers third law for a and double this result:<br />

2<br />

1/3<br />

(365.256 days)<br />

10<br />

2 29.925 10 m<br />

2<br />

(4 ) / ( GM )<br />

2<br />

1/3<br />

(84 years)<br />

10<br />

2 573.95 10 m<br />

2<br />

(4 ) / ( GM )<br />

Copyright<br />

2014 Pearson Education, Inc.

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