1.Sitting cross-legged on the ground II. Lying horizontally flat on the ground
III. Standing on both feet and not moving
IV. Seated motionless on a rocking chair with both feet on the ground

Gravitational potential energy is the energy stored in a body due to its heightfrom the ground. The amount of gravitational potential energy a person has depends on the distance of his centre of mass from the ground. Given that a person's centre of mass is at his navel (just below his stomach), arrange the
positions, I, II, III and IV, in the order that will give the person an increasing
gravitational potential energy.
[1]​

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

do you have a formula possibly

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.