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Answers to Chapter 5 problems

 

5.1.1   (a) 6.4 × 1020 N     (b) 2.3 × 1020 N

5.2.1   (a) 5.9 × 10−3 m s−2   (b) 3.3 × 10−5 m s−2. However tides are influenced by the gradients of the gravitational field strengths of the Sun and Moon rather than their magnitudes. These gradients are, respectively, − 7.9 × 10−14 s−2 and − 1.7 × 10−13 s−2 so that the influence of the Moon is greater.

5.5.1   6.39 × 10−10 N

5.5.2    \( { 2GmM\over R^2} \left[ {1- {d\over \sqrt{R^2+d^2}} } \right] \)

5.5.3   85 minutes

5.6.1   14.4 m s−1

5.6.2   76°

5.7.1   (b) 6,516 s ;   1,678 m s−1   (c) The spring balance reads 0 N throughout the oscillation.

5.7.2   (a)  √(2gR(1 − cosq)   (b) − 2g(1 − cosq)   (c) gsinq ; 48.18°

5.7.3   5.94 × 106 J

5.7.4   (a) − 4.2 × 108 J   (b) − 7.8 × 108 J   (c) − 6.7 × 109 J

5.9.1   85 kJ

5.9.2   27.0 N

5.9.3   (a) 2.5 s   (b) 88 mJ   (c) 0.11 m

5.10.1   3,569 m

5.10.2   (a) 0.3 nm (b) 9.7 × 10−7 N

5.10.3 

5.10.4   2.1 m

5.10.5   \( m_2 \sqrt{{2G \over m_1+m_2} \left( {1 \over r} - {1 \over r_0} \right)} \)     and     \( m_1 \sqrt{{2G \over m_1+m_2} \left( {1 \over r} - {1 \over r_0} \right)} \)

5.11.1   (a) 1 × 10−34 J s   (b) 2.7 × 1040 J s   (c) 0.2 J s

5.12.1   (a) 2,149 m s−1   (b) 112 km   (c) 560 m s−1

5.12.2   (a) 455 km   (b) 7,645 m s−1   (c) 5,609 s

5.12.3   42,300 km

5.12.4   0.67 m s−1;    0.02 J

5.12.5   (a) 7.3 km s−1   (b) 8.1 × 1013 J s   (c) − 4.0 × 1010 J   (d) 2.6 × 109 J

5.12.6   270 m s−2

5.12.7   584 m s−1 ;   242 m s−1

5.13.1  

5.13.2   (a) 0.025 kg m2 s−1; 0.079 J   (b) 25.13 rad s−1 (4.0 revs s−1)   (c) increases by 0.237 J

5.13.3   0.237 J

5.13.4

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Mansfield and O'Sullivan, Understanding Physics, 3rd ed., John Wiley & Sons, Chichester (2020),

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