Escape velocity on the surface of earth is 11.2 km/s. Escape velocity from a planet whose mass is the same as that of earth and radius 1/4 that of earth is
2.8 km/s
15.6 km/s
22.4 km/s
44.8 km/s
ve=2GMR=11.2km/s vp=2GMPRP=2GMR4=42GMR=22GMR=2×11.2km/s=22.4km/s