How does air resistance affect an object’s speed?

When air resistance acts, acceleration during a fall will be less than g because air resistance affects the motion of the falling objects by slowing it down. Air resistance depends on two important factors - thespeed of the object and its surface area. Increasing the surface area of an object decreases its speed.

Hot air rises to the ceiling and as it cools on the far side of the ceiling it sinks back down to the floor. That's why the floor is cooler than the ceiling.