The feeling of weightlessness occurs because

The feeling of weightlessness occurs because of the absence of a force of support on your body.

Explanation:

In the cases in which your body's experimenting "free fall", that is to say, when it's falling at the same acceleration than gravity, it means your body lacks support. On the other hand, the sensation of having weight is produced because you stand on the floor or float in water, perceiving its support.

b. false

explanation:

suppose a rock in free fall is dropped off a cliff. after falling for 5 seconds, its speed would not be 100 m/s.