Q.

A planet having mass 9Me and radius 4Re, where Me and Re are mass and radius of Earth respectively, has escape velocity in km/s given by: (Given escape velocity on Earth Ve=11.2×103 m/s)                        [2023]

1 67.2  
2 16.8  
3 33.6  
4 11.2  

Ans.

(2)

VP=2GMPRP, VE=2GMERE

VPVE=2GMPRP2GMERE=RERP×MPME

VP=14×9×VE=32VE

VP=32×11.2 km/sec=16.8 km/sec