Here, mass of the rocket `m =3xxx10^6kg`
velocity acquired by the rocket, `upsilon =1km//s =1000m//s`
height attained by the rocket, h =25km = 25000m
(a) Potential energy of the rocket, `E_p = mgh =(3xx10^6kg)(10m//s^2) (25000m) = 7.5xx10^(11)J`
(b) Kinetic energy of the rocket, `E_k = (1)/(2)m upsilon^2 =(1)/(2)(3xx10^6kg)(1000m//s)^2 = 1.5xx10^(12)J`