A ball of mass \( 100 \, \text{g} \) is projected with velocity \( 20 \, \text{m/s} \) at \( 60^\circ \) with horizontal. The decrease in kinetic energy of the ball during the motion from point of projection to highest point is:
\( 5 \, \text{J} \)
zero
\( 20 \, \text{J} \)
\( 15 \, \text{J} \)