Gravitation question bank (Physics)

By how many times the energy of a satellite has to be increased to shift it from an orbit of radius 'r' to $\dfrac{5}{2}\ r$ ?

A planet of mass $m$ moves in an elliptical orbit around the Sun of mass $M$. Let $r_1$ be the distance at aphelion and $r_2$ be the distance at perihelion. If $v_1$ and $v_2$ are the velocities of the planet at these points, then ratio of kinetic energy at aphelion to kinetic energy at perihelion is