Question

In which case do we consider the potential energy us equal to zero?

Answer 1

Potential energy is the energy possessed by an object by the virtue of its position.

It is given by :

P. E = mgh

Where :

m = mass

g = acceleration due to gravity

H = height from the surface of the earth.

For potential energy to be zero, the following conditions must be fulfilled.

1.) The mass should be zero

2.) The gravitational acceledation
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3.) The position of the object is on the ground meaning the height is zero.

Case 1 and 2 are impossible since acceleration due to gravity at no point can be zero and the mass of zero means the particle does not exist.

We therefore remain with 3 which simply implies that the object is on the ground and thus the P. E is zero at this point.