# Weightlessness and free fall on oil drop experiment

Suppose I have an oil drop which is negatively charged placed in a box with the bottom of the box negatively charged. When this box and oil drop is placed on a table where the box is stationary, the oil drop is stationary in the middle of the box. Hence, we can conclude that the force of repulsion between the negatively charged oil drop and bottom surface of the box is EQUAL to the the weight.

So now, I drop the whole system from the top of a building. Assume there is no air resistance. Since the whole system is in free fall, is it correct to say that for the same oil drop and box, the oil drop will now move upwards towards the top of the box?

Since free fall is the same as being in outer space with zero gravity.

• Can you think of any reasons why that might not be true? Commented May 25, 2021 at 1:56
• A related question (relative to MP 2Ring): if the droplet was in static equilibrium before you dropped the box, what do you expect when the force of gravity is suddenly removed from the free body diagram? Commented May 25, 2021 at 2:29
• I mean nothing unique about oil droplets here. If you drop a bottle of water the distribution of water inside the bottle will shift upward Commented May 25, 2021 at 4:13
• So this is true right? Just making sure because I was having a debate with my friend and he said the otherwise. Commented May 25, 2021 at 5:08
• he said the otherwise because both the box and the oil drop is moving together so nothing will change. Commented May 25, 2021 at 5:28