Free fall is any motion of a body where gravity is the only force acting upon it.
Notice that an object can be considered to be free falling even if it is moving upwards.
Watch these videos and describe in your own words why objects of different mass accelerate at the same rate in a vacuum.
Study the photo of a ball in free fall. How can you tell it is accelerating?
Estimate the acceleration of the ball given that the scale measures in centimeters and the camera took 20 pictures per second.