Let the mass of the body be m and velocity of the body be v, such that it has momentum p and kinetic energy E. Momentum, p=mv ⇒p2=m2v2 Kinetic energy, E=
1
2
mv2 ⇒E=
p2
2m
Hence, the nature of the graph between momentum of a body and its kinetic energy is parabola. i,e., E∝p2