$12\mathrm{.}8$ A rocket has a mass ratio of $MR=0\mathrm{.}10$ and a mean specific impulse of $365$ s $.$ The flight trajectory is described by a constant dynamic pressure of $q_0=50$kPa. The mean drag coefficient is approximated to be $0\mathrm{.}25,$ the vehicle initial mass is $m_0=100,000kg,$ and the vehicle $($maximum$)$ frontal cross$-$sectional area $A_f$ is $5m^2.$ For a burn time of $100$ s $,$ calculate the rocket terminal speed while neglecting gravitational effect.