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7.Gravitation
normal
Escape velocity at the surface of earth is $11.2\,km/sec$ . If radius of planet is double that of earth but mean density same as that of earth then the escape velocity will be ........ $km/sec$
A
$11.2$
B
$5.5$
C
$15.5$
D
$22.4$
Solution
$V_{e}=\sqrt{2 g e}=\sqrt{2 \times \frac{4}{3} \pi R p g \times R}$
$\mathrm{V}_{\mathrm{e}} \times \mathrm{R}$
$\frac{V_{e}}{V_{e}^{1}}=\frac{R}{R^{1}} \Rightarrow V_{e}^{1}=2 V_{e}=2 \times 11.2$
$\mathrm{V}_{\mathrm{e}}^{\mathrm{l}}=22.4 \mathrm{km} / \mathrm{s}$
Standard 11
Physics
