Question

A stone weighing 1 kg is dropped from rest from a height of 4 metres above the ground. When it has free-fallin 1 metre its total energy with respect to the ground is.

Answer 1

Hint: Potential energy is the energy that an item has due to its location in relation to other objects, internal tensions, electric charge, or other reasons. Because the work of potential forces acting on a body moving from a start to an end position is defined only by these two positions and not by the body's trajectory, a function known as potential may be assessed at these two places to determine this work. We use this concept and its corresponding formula here.

Formula used
${E_P} = mgh$
M = mass
G = acceleration due to gravity
H = height

Complete step by step solution:
Free fall is defined in Newtonian physics as the motion of a body in which gravity is the sole force acting on it. A body in free fall has no force acting on it under general relativity, where gravity is reduced to a space-time curvature. In the technical definition of the phrase "free fall," an item may or may not be falling down in the common sense. Although an item travelling upwards is not generally regarded to be falling, it is said to be in free fall if it is simply subjected to the force of gravity. The Moon is therefore in free fall around the Earth, despite the fact that its orbital speed keeps it at a great distance from the planet's surface.
${E_P} = mgh$
From the given equation
M = 1 kg
g = $10m{s^{ - 2}}$
H = 1 m
\[{E_P}{\text{ }} = {\text{ }}mgh{\text{ }} = {\text{ }}1{\text{ }} \times {\text{ }}10{\text{ }} \times {\text{ }}4{\text{ }}\]
\[ \Rightarrow {E_P}{\text{ = }}40J{\text{ }}\]
The item has 40 J of potential energy but no kinetic energy at the start. The total mechanical energy is 40 J (${E_p} + {E_K}$).

Note:
Forces and potential energy are inextricably connected. If the work done by a force on a body moving from point A to point B is independent of the path between these points (if the work is done by a conservative force), the work done by this force measured from point A assigns a scalar value to every other point in space and defines a scalar potential field. In this situation, the force may be described as the inverse of the potential field's vector gradient.