what is conservation of energy ?define properly with derive it.
Answers
Answer:
In physics and chemistry, the law ofconservation of energy states that the totalenergy of an isolated system remains constant; it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.
Answer:
law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another.
Let us now prove that the above law holds good in the case of a freely falling body.
Let a body of mass 'm' placed at a height 'h' above the ground, start falling down from rest.
In this case we have to show that the total energy (potential energy + kinetic energy) of the
body A, B and C remains constant i.e, potential energy is completely transformed into kinetic energy.
conservation of energy Body of mass m placed at a height
At A, Potential energy = mgh
Kinetic energy = 0 [the velocity is zero as theobject is initially at rest]
Total energy at A = Potential energy + Kinetic
energy.
Total energy at A = mgh ..1
At B Potential energy = mgh = mg(h - x) [Height from the ground is (h-x)] Potential energy = mgh - mgx Kinetic energy = ½ mv².The body covers the distance x with a velocity v.
We make use of the third equation of motion to obtain velocity of the body.
Here, u=0, a=g and s=x
Kinetic energy = mgx
Total energy at B = Potential energy + Kinetic
energy
Total energy at B = mgh..2
At C, Potential energy = m x g x 0
Potential energy = 0
Kinetic energy = ½ mv²
The freely falling body has covered the distance
h.
Here, u=0, a=g and s=h
Kinetic energy = 1/2 mv²
= Kinetic energy = mgh
Total energy at C = Potential energy +
energy
Total energy at C = mgh ..3
It is clear from equations 1, 2 and 3 that the total energy of the body remains constant at every point. Thus, we conclude that law of conservation of energy holds good in the case of a freely falling body.