Work = (force) x (distance)
Force = weight of the barbell = (mass) x (gravity) = (2.5 kg) x (9.8 m/s²)
Work = (2.5 x 9.8 newtons) x (3 meters) = 74 newton-meters = 74 joules.
It takes 74 joules to lift the 2.5-kg load 3 meters up off the floor.
After that, as long as the load is held motionless, no more work is done.
