How fast (in `m^2//s`) is area swept out by
(b) the radius from earth to moon ? Given distance of sun to earth `=1.496xx10^(11)m`, distance of earth to moon `=3.845xx10^8m` and period of revolution of moon `=271/3`days.

Explanation

Here , `r=3.845xx10^8 m`,
`T=271/3days =(82)/3xx60xx60xx24s`
`therefore` The rate, at which the area is swept out by radius from the earth to moon,
`(dA)/(dt)=(pixx(3.845xx10^8)^2)/((82)/3xx24xx60xx60)`
`=1.97xx10^(11)m^2*s^(-1)`