KE (kinetic energy)= .5mv^2
m=mass
v=velocity
KE=(.5)(2kg)(15m/s)^2=225 J
potential energy is 225 J also
As the ball's energy will be conserved and transformed from kinetic to potential as it is being thrown into the air. The higher it is thrown, the less kinetic energy it has but more potential energy it has. At the top, all energy is potential.
See energy-work theorem for more
