state and explain law of conservation of energy
Answers
Explanation:
Energy is required for the evolution of life forms on earth. In physics, it is defined as the capacity to do work. We know that energy exists in different forms in nature. You have learned about various forms of energy – heat, electrical, chemical, nuclear, etc. In this article, we will learn about the laws and principles that govern energy. This law is known as the law of conservation of energy.
What is the Law of Conservation of Energy?
The law of conservation of energy states that energy can neither be created nor be destroyed. Although, it may be transformed from one form to another. If you take all forms of energy into account, the total energy of an isolated system always remains constant. All the forms of energy follow the law of conservation of energy. In brief, the law of conservation of energy states that
In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved.
conservation of energy
Example of Energy Transformation
So in an isolated system such as the universe, if there is a loss of energy in some part of it, there must be a gain of an equal amount of energy in some other part of the universe. Although this principle cannot be proved, there is no known example of a violation of the law of conservation of energy.
The amount of energy in any system is determined by the following equation:
Law of Conservation of Energy
UT is the total energy of a system
Ui is the initial energy of a system
Q is the heat added or removed from the system
W is the work done by or on the system
The change in the internal energy of the system is determined using the equation
Law of Conservation of Energy
Suggested Reading
First Law of Thermodynamics
Conservation of Mechanical Energy
Law of Conservation of Energy Derivation
Considering the potential energy at the surface of the earth to be zero. Let us see an example of a fruit falling from a tree.
Consider a point A, which is at height ‘H’ from the ground on the tree, the velocity of the fruit is zero hence potential energy is maximum there.
E = mgH ———- (1)
When the fruit is falling, its potential energy is decreasing and kinetic energy is increasing.
At point B, which is near the bottom of the tree, the fruit is falling freely under gravity and is at a height X from the ground, and it has speed as it reaches point B. So, at this point, it will have both kinetic and potential energy.
E = K.E + P.E
P.E = mgX ——— (2)
According to third equation of motion,
v2=2g(H–X)⇒12mv2=12m.2g(H–X)⇒K.E=12m.2g(H–X)⇒K.E=mg(H–X)
K.E=mg(H-X)——– (3)
Using (1), (2) and (3)
E = mg(H – X) + mgX
E = mg(H – X + X)
E = mgH
Similarly, if we see the energy at point C, which is at the bottom of the tree, it will come out to be mgH. We can see as the fruit is falling to the bottom and here, potential energy is getting converted into kinetic energy. So there must be a point where kinetic energy becomes equal to potential energy. Suppose we need to find that height ‘x’ from the ground. We know at that point,
K.E = P.E
=> P.E = K.E = E2 ——– (4)
E2 is the new energy
Where, E = mgH2
H2 is the new height.
As the body is at height X from the ground,
P.E = mgX ——— (5)
Using (4) and (5) we get,
mgX=mgH2⇒X=H2
H2 is referred to the new height
HOPE IT HELPS YOU ..............
Answer:
??????¿??????????????