# The propellant in a single stage sounding rocket occupies $60 \%$ of its initial mass. If all of it is expended instantaneously at an equivalent exhaust velocity of $3000 \mathrm{~m} / \mathrm{s}$, what would be the altitude attained by the payload when launched vertically? [Neglect drag and assume acceleration due to gravity to be constant at $\left.9.81 \mathrm{~m} / \mathrm{s}^{2} .\right]$ (A) $315 \mathrm{~km}$ (B) $335 \mathrm{~km}$ (C) $365 \mathrm{~km}$ (D) $385 \mathrm{~km}$

## Question ID - 156248 | SaraNextGen Top Answer The propellant in a single stage sounding rocket occupies $60 \%$ of its initial mass. If all of it is expended instantaneously at an equivalent exhaust velocity of $3000 \mathrm{~m} / \mathrm{s}$, what would be the altitude attained by the payload when launched vertically? [Neglect drag and assume acceleration due to gravity to be constant at $\left.9.81 \mathrm{~m} / \mathrm{s}^{2} .\right]$ (A) $315 \mathrm{~km}$ (B) $335 \mathrm{~km}$ (C) $365 \mathrm{~km}$ (D) $385 \mathrm{~km}$

Answer Key / Explanation : (D) -

(D) $385 \mathrm{~km}$