Body A of mass 4m moving with speed u collides with another body B of mass 2m, at rest. The collision is head on and elastic in nature. After the collision the fraction of energy lost by the colliding body A is :
(1) $1\over9$
(2) $8\over9$
(3) $4\over9$
(4) $5\over9$
(1) $1\over9$
(2) $8\over9$
(3) $4\over9$
(4) $5\over9$