Here is a demonstration that shows that all objects experience the same acceleration, a = -g, in y-direction. And this acceleration is independent of the velocity of the object.
This is the story that goes along with our demonstration:
A monkey has escaped from the local zoo and is hanging from a branch. The zookeeper (right side of the picture, with the helmet) wants to re-capture the monkey. He has a tranquilizer gun (well, ok, we use an air-pressure cannon). The zookeeper knows that the monkey will immediately let go of the branch as soon as he hears the gun (we simulate this effect with a magnetic switch at the exit of the gun-barrel).
Question:
How can we hit the monkey in mid-air?
Answer:
One only has to aim at the initial position of the monkey. (We have
indicated this on the first frame with a black line.) If what we have
said above is true, then monkey and bullet should fall with the same
acceleration, and the monkey will be hit in mid-fall.
This demonstration is hard to capture on film. Therefore we have captured it is slow-motion. In addition, the location of the bullet is hard to see. Thus we have marked the bullet with a black circle around it on each frame.