Question

A body of mass 10 kg falls on the surface of earth from
infinity. The kinetic energy of body on reaching earth surface
is (radius of earth 6400 km, g = 9.8 m/s)
69 x 108 J
18 x 103 J
20 x 104 J
62.7 x 107 J​

Answer 1

Answer:

=x radius+diameter=2500

=radius=1250

Answer 2

  ${ \boxed{ \boxed{{ {\red{ \blue{\sf{⋆⫷❥ᴀ᭄{n }}§₩ΣR⫸⋆}}}}}}}$

ui+ki=uf+kf

⇒0+0=GMm/R+1/2 mv×v

⇒21mv2=(GMm×R×R)×R

=mgR

=100×9.8×6400×1000

=6272000×1000

=6.27×109J

Hence,

option (A) is correct answer.