Question

Find the angular momentum of halley's comet at perihelion."

Answer 1

Answer:

When the comet is closest to the Sun, at the location specified by the position vector r → 1 (“perihelion”), it is x m from the Sun, and its speed is x m/s. ... Calculate the translational (orbital) angular momentum of the comet, relative to the Sun, at both locations.

Answer 2

the comet's kinetic energy (KE)   =  1/2 mv2      where m is the mass of the comet
    the sun's kinetic energy is negligible in comparison  

b) the gravitational energy (GE) of the comet-sun system is   =   - G m Msun/r
    where M is the mass of the sun, G is Newton's Gravitational Constant

c) the total energy (TE) is therefore  =  1/2 mv2  - G m Msun/r

    because the mass m of the comet is generally unknown or known inaccurately,
    it is best to reformat these three energies as energies per (comet) mass:

    KE/mass   =  1/2 v2  ;  in order to have the units in standard SI (J/kg), convert the orbit speed from km/s to m/s
   
    GE/mass   =  - GMsun/r  ;  in order to have units of J/kg, convert the comet-sun distance from au to m
                                           it is important to use the most accurate values of quantities available
                                           G  =  6.6742 x 10-11 m3/kg/s2
                                           Msun  =  1.9891 x 1030 kg
                                           1 au  =  1.495 978 707  x 1011 m

    TE/mass  =  1/2 v2  - G Msun/r