The mass of (an imaginary) planet is four times that of the earth and its radius is double the radius of the earth. The escape velocity of a body from the earth is `11.2xx10^(3)m//s`. Find the escape velocity of a body from the planet.

Explanation

Data : `M_(2)=4M_(1), R_(2)=2R_(1)`,
`v_("1esc")=11.2xx10^(3)m//s.`
`v_("esc")=sqrt((2GM)/(R))`
`therefore (v_("2esc"))/(v_("1esc"))=sqrt((M_(2))/(M_(1))xx(R_(1))/(R_(2)))=sqrt(4xx(1)/(2))=sqrt2`
`therefore v_("2 esc")=sqrt2 v_("1esc")=1.414xx11.2 xx10^(3)m//s`
`=15.84xx10^(3)m//s = 15.84km//s`
This is the escape velocity of a body from the planet .