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                                    m _
                                 ρ =       ∴  m = ρV                        Example 15.4, p. 399


                                    V
                                                                          What is the mass of the Sun, in kilograms, based on the revolution
                                                                          period and distance of Jupiter?
                                            m ice  = ρ ice  V  ice
                                                   g
                                                  _
                                                                                            11
                                               = 0.917       (7.0 × 10  cm )       r p  = 7.78 × 10  m
                                                             7
                                                                3


                                                   cm 3                           T j  = 11.86 yr
                                               = 6.4 × 10  g                                −11 N ⋅ m 2
                                                    7
                                                                                               _
                                                                                   G = 6.67 × 10


                                                                                                kg 2
                   Determine the energy required to heat the ice to its melting point:
                                                                                 m s  = ?
                                                                                       2 3
                                     7
                                                                                     _
                          m ice  = 6.4 × 10  g                                   m s  =    4π r
                                   _                                                  Gt 2
                                    cal

                               c ice  = 0.500

                                   g ⋅ °C
                                                                          Convert time to seconds.
                              T i  = −220 °C
                                                                                                    7 s _
                                                                                           (
                                                                                                     yr)

                             T f  = 0 °C                                          T j  = 11.86 yr  3.154 × 10
                              Q = ?                                                          8
                                                                                  T j  = 3.741 × 10  s
                                  Q = mc ΔT                                                   2       11  3
                                                                                            4π (7.78 × 10  m)
                                                                                     ____


                                                                                 m s  =


                                            (
                                                  cal
                                                 g ⋅ °C)
                                         7
                                =  (6.4 × 10  g)  0.500    _                         (   6.67 × 10 −11 N ⋅ m    2   (3.741 × 10  s) 2
                                                                                                   2 )
                                                                                                _
                                                      (220 °C)

                                                                                                              8



                                                                                                 kg
                                                       cal
                                                     ( g ⋅ °C)
                                = (6.4 × 10 )(0.500)(220)(g)     _                    =   ___ __
                                         7
                                                                                                    11 3
                                                                                           2
                                                                                                                  3
                                                            (°C)
                                                                                         4π (7.78 × 10 )
                                                                                                                (m)










                                                                                                        8 2
                                                                                     (6.67 × 10 −11 )(3.741 × 10 )  kg ⋅ m  2
                                                                                                            _
                                        9


                                                                                                                 ⋅ m

                                = 7.0 × 10  cal                                                             ( _     )    2

                                                                                                              2
                                                                                                              s

                   Use the solar energy received from Table 15.1 and multiply by the area                       kg 2   (s)
                   and the duration of time to determine the energy received:            4π (4.71 × 10 )
                                                                                                   35
                                                                                           2
                                                                                       =   ___               kg



                                                                                                       17
                                               _                                     (6.67 × 10 −11 )(1.400 × 10 )
                                                cal
                          solar energy received = 0.08


                                                 2
                                               cm  ⋅ s                                      37
                                                                                      1.86 × 10
                                                                                       =    _
                                                                                              kg


                                          t = 10 h                                   9.338 × 10 6
                                                  6
                                         A = 3.5 × 10  cm 2                            =  1.99 × 10  kg
                                                                                            30
                                        Q = ?
                          Q = (solar energy received)(At)
                   Convert time to seconds:                                CHAPTER 16
                                        3 s _
                                          )
                                 (
                            t = 10 h  3.6 × 10                            Example 16.2, p. 409

                                                                          The observer is in the Southern Hemisphere because the altitude
                                         h
                                    4
                              = 3.6 × 10  s                               is measured above the northern horizon. Determine the difference
                                                                          between the zenith and the altitude and subtract 23.5°. The zenith is
                                 _           6  2       4
                                  cal
                          Q = 0.08         (3.5 × 10  cm )(3.6 × 10  s)   90° above the horizon.

                                   2
                                 cm  ⋅ s
                                                                                   zenith = 90°  latitude = (zenith − altitude) + 23.5°
                                               4 _
                              = 0.08(3.5 × 10 )(3.6 × 10 )      cal     (cm )(s)  altitude = 40.0°    = (90°−40.0°) − 23.5°
                                                         2
                                       6

                                                   2
                                                 cm  ⋅ s
                                                                                 latitude = ?
                              = 1.0 × 10  cal                                                         = 50.0° − 23.5°
                                    10
                                                                                                      = 26.5° S
                   Compare the energy received to the energy required to heat the ice to
                   its melting point:
                                                                          Example 16.4, p. 414
                                            9
                                10
                          1.0 × 10  cal > 7.0 × 10  cal                   Determine the ratio in hours between an apparent solar day and a
                                                                          sidereal day, and multiply by the number of mean solar days in one
                   ∴ The ice temperature could rise to the melting point .
                                                                          sidereal year.
                                                                                     day length sidereal  = 23 h 56 min 4 s
                                                                                 day length mean  solar  = 24 h
                                                                                            year length = 365.25636 mean solar days (msd)
                                                                                         sidereal days = ?
                   638     APPENDIX D  Solutions for Follow-Up Example Exercises                                         D-6
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