The Nets have often cited a lack of energy as a problem after their losses this season. Last night, the Bulls showed them how far energy can carry a team. Led by Chicago’s human ball of energy, Joakim Noah, the Bulls beat the Nets, 96-85, in front of a sellout crowd of 22,414 inside United Center in a game that was much more lopsided than the final score indicated. The Nets have now lost four of their last five games, and have dropped into sixth place in the Eastern Conference standings. “We are not playing well,” Nets interim coach P.J. Carlesimo said. “We need to play a lot better.” Besides obviously getting better play, what the Nets (34-26) could use is a dose of the energy and enthusiasm Noah brings to the floor on a nightly basis. After superstar point guard Derrick Rose tore his left ACL during Chicago’s first-round playoff loss last year and the Bulls (34-25) renovated — and in several ways downgraded — their terrific bench from last season during the summer, some wondered if the Bulls would be able to remain in the Eastern Conference this season while Rose continues to rehab from his surgery.