Explanation:

We know the orbital velocity of a satellite around a planet of mass M having a radius of orbit (r>R)

     Vo = √GM/r

? Time period = 2πr/V

                        = 2π√R^3/GM

here G and M are constant.

  Time period depends only on radius (height above earth)

∴ Time perois for satellite near earth surface

=2π √R/g

=2π/sqrt π^2(√6400×1000

?    

 [?g≈π ]

=84min=1hr+24min