Q. A rocket is launched with velocity $10\ km/s$. If radius of earth is $R$, then maximum height attained by it will be
A) $2R$
B) $3R$
C) $4R$
D) $5R$
Explanation
(c) If the body is projected with velocity $v(v < v_{e})$ then height up to where it rises,
$h = \frac{R}{\frac{v_{e}^{2}}{v^{2}} - 1}$
$\Rightarrow h = \frac{R}{\left( \frac{11.2}{10} \right)^{2} - 1} = 4R\ (approx.)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.