Original: However, since objects in microgravity still retain their mass and inertia, an astronaut must exert ten times as much force to accelerate a 10kilogram object at the same rate as a 1kilogram object.
Simplified: However, the objects still have their mass and inertia. Astronaut must use ten times as much force to accelerate a ten-kilogram object at the same rate as a one-kilogram object.