During motion of a planet from perihelion to aphelion the work done by gravitational force of sun on it is ...........

If the angular momentum of a planet of mass $m$, moving a round the Sun in a circular orbit its $L$, about the center of the Sun, its areal velocity is

The orbital angular momentum of a satellite revolving at a distance $r$ from the centre is $L$. If the distance is increased to $16r$, then the new angular momentum will be

A comet orbits the sun in a highly elliptical orbit. Does the comet have a constant $(a)$ linear speed, $(b)$ angular speed, $(c)$ angular momentum, $(d)$ kinetic energy, $(e)$ potential energy, $(f)$ total energy throughout its orbit? Neglect any mass loss of the comet when it comes very close to the Sun.

If the distance between the earth and the sun becomes half its present value, the number of days in a year would have been

Let the speed of the planet at the perihelion Pin Figure be $v_{p}$ and the Sun-planet distance $SP$ be $r_{ P }$ Relate $\left\{r_{P}, v_{P}\right\}$ to the corresponding quantities at the aphelion $\left\{r_{A}, v_{A}\right\} .$ Will the planet take equal times to traverse $B A C$ and $C P B ?$