Question

A cube of mass 1=8.1 kg is sitting on top of a second cube of the same size and mass 2=0.5 kg while both are in free fall. Ignoring any air resistance, what is the magnitude of the normal force with which the bottom cube is acting on the top cube?

Answer 1

In free fall, both cubes accelerate at the same rate due to gravity, resulting in a normal force of zero between the two cubes since there is no additional force being exerted by the upper cube on the lower one.

Step-by-step explanation:

The question is asking about the normal force acting between two cubes in free fall. When objects are in free fall, the only force acting on them is gravity. Therefore, both cubes accelerate downwards at the same rate, which is the acceleration due to gravity (g = 9.80 m/s²). Since there is no relative motion between the two cubes, and they are not on a non-accelerating horizontal surface, the normal force between them would be zero. This is because the top cube is not exerting any additional force on the bottom cube other than its weight, and since they are both accelerating at the same rate, the bottom cube does not push up on the top cube with any additional force.