Mechanical Energy Class 11 Project
Mechanical Energy Class 11 Project
Mechanical Energy Class 11 Project
In
nature, one can see its manifestation, in various forms and it can only be
measured indirectly. Mechanical energy is all-encompassing and
concerned with every system in nature. Conservation of this energy is
the principle which can be used to predict the behavior of any system in
nature, if we know the initial conditions.
The sum total of potential and kinetic energies of a system, is the net
mechanical energy of the system. It is incorrect to say that this energy is
something just connected with machines. It is the totality of all forms of
energy associated with a system. The system may be anything, ranging
from a ball tossed in air, to a molecule of water, or just an atomic
nucleus. It is measured in the SI unit of 'Joule'.
In physical sciences, mechanical energy is the sum of potential energy
and kinetic energy. It is the energy associated with the motion and
position of an object. The principle of conservation of mechanical
energy states that in an isolated system that is only subject to
conservative forces, the mechanical energy is constant. If an object is
moved in the opposite direction of a conservative net force, the potential
energy will increase and if the speed (not the velocity) of the object is
changed, the kinetic energy of the object is changed as well. In all real
systems, however, non-conservative forces, like frictional forces, will be
present, but often they are of negligible values and the mechanical
energy's being constant can therefore be a useful approximation. In
elastic collisions, the mechanical energy is conserved but in inelastic
collisions, some mechanical energy is converted into heat. The
equivalence between lost mechanical energy (dissipation) and an
increase in temperature was discovered by James Prescott Joule.
TME = PE + KE
The diagram below depicts the motion of Lee Ben Fardest (esteemed
American ski jumper) as he glides down the hill and makes one of his
record-setting jumps.
Conservation of Energy:-
The Law of Conservation of Energy: Energy cannot be created or
destroyed, but is merely changed from one form into another.
The sum total of an object’s kinetic and potential energy at any given
point in time is its total mechanical energy. The law of conservation of
energy says “Energy can neither be created nor be destroyed.”
Conservative Force:-
A conservative force has following characteristics:
ΔK + ΔV = 0 or Δ(K + V) = 0
Therefore for every displacement of Δx, the difference between the sums
of an object’s kinetic and potential energy is zero. In other words, the
sum of an object’s kinetic and potential energies is constant under a
conservative force. Hence, the conservation of mechanical energy is
proved.
Now, the object retraces its path, this time from position B to
position A. Back at position A, the object’s kinetic energy has
been restored to its initial level. Object’s Potential energy is zero.
Now, the object travels the exact same path as AB, but in reverse
direction of AC.
Here, V is the potential energy of the object in joules (J), m is the mass
of the object in kilograms, g is the gravitational constant of the earth (9.8
m/s²), and h is the height of the object from earth’s surface. Now, we
know that the acceleration of an object under the influence of earth’s
gravitational force will vary according to its distance from the earth’s
centre of gravity.But, the surface heights are so minuscule when
compared to the earth’s radius, that, for all practical purposes, g is taken
to be a constant.
Certificate
This is certified to be the
bonafide work of the student in
the during the academic year
2018/2019.