Question

The escape velocity of an object on a planet whose g value is 9 times on earth and whose radius is 4 times that of earth in km/s is

• A. 67.2
• B. 33.6
• C. 16.8
• D. 25.2

Answer 1

Answer: (A)

67.2

Answer 2

$\frac { v _ { p } } { v _ { e } } = \sqrt { \frac { g _ { p } } { g _ { e } } \times \frac { R _ { p } } { R _ { e } } } = \sqrt { 9 \times 4 } = 6$∴ $v _ { p } = 6 \times v _ { e } = 67.2 \mathrm {~km} / \mathrm { s }$