Question

The escape velocity for the earth is $v_e$ . The escape velocity for a planet whose radius is four times and density is nine times that of the earth, is :

• A. $36v_e$
• B. $12v_e$
• C. $6v_e$
• D. $20v_e$

Answer 1

The correct option is A $36v_e$

The relation between the escape velocity and the radius is given as

$v_e=Kr\sqrt{\rho }$

If the radius of the planet becomes four times and the density nine times then the escape velocity becomes

$v_{e2}=36v_e$