A100 kg object and a 10 kg object are dropped simultaneously in a vacuum. which of the following statements is true?
both objects will accelerate at 9.8 m/s2
the 100 kg object will accelerate faster than the 10 kg object.
the 10 kg object will accelerate faster than the 100 kg object.
air resistance will slow the fall of the 100 kg object more than the 10 kg object.

Both objects will accelerate at 9.8 m/s².

Explanation:

According to given condition, a 100 kg object and a 10 kg object are dropped simultaneously in a vacuum. If there is no air resistance, when two objects of same or different masses will reach the ground at same time. The rate of descent does not depend on the amount of matter contained inside the object.

In the vacuum, no air resistance is present. Both of the objects will accelerate at 9.8 m/s² i.e. under the action of gravity.

So, the correct option is (a). Hence, this is the required solution.  

probably not if net force is zero