Final answer:
Without air resistance, both objects of mass m and 2m, when dropped from the same height, will fall at the same rate due to the constant acceleration of gravity and hit the ground simultaneously.
Step-by-step explanation:
When two objects, one of mass m and the other of mass 2m, are dropped from the top of a building without air resistance, they will both fall at the same rate. This is because the acceleration due to gravity is constant at 9.80 m/s² and is independent of the mass of the falling objects. Since there's no air resistance to oppose their motion, both objects experience free-fall and hence, they will reach the ground at the same time. In an idealized situation without air resistance, all objects in free-fall near the surface of the Earth will accelerate at this constant rate regardless of their mass.