The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are K_A, K_B and K_C, respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then :

K_A > K_B > K_C

Point A is perihelion and C is aphelion.

v.r = constant 

\(\Rightarrow v = \frac{1}{r}\)

So, v_A > v_B > v_C

So, K_A > K_B > K_C