Question

If the earths mass increases to twice of its present value and radius of the earth bocomes half,the escape velocity becomes

Answer 1

the mass of the earth is M, and redious is R. escape velocity is v=√(2GM/R),
in present the mass of the earth is 2M, and the redious is R/2, then the escape velocity of the earth is =√(8GM/R)=2v.