The work done on the mass is (force) · (distance) = 25·m joules.
That work shows up as kinetic energy of the mass = (1/2)·(mass)·(speed)² .
(1/2)·(mass)·(speed²) = 25m joules
(1 kg)·(speed²) = 25m joules
speed² = (25m joules) / (1 kg) = 25m meters²/sec²
speed = 5·√m meters/sec
