Two identical 0.25kg hockey pucks slide frictionlessly on level ice. Puck A travels east at 3.0m⋅s−1, while puck B travels north at 4.0m⋅s−1. The pucks collide at the corner of their paths and stick together. What fraction of the system’s initial kinetic energy is lost in the collision?
a) 75\%
b) 50\%
c) 40\%
d) 0\%