Energy (Physics)

Introduction

Energy is a fundamental concept in physics that describes the capacity to do work or produce an effect.
Understanding energy is crucial in explaining various physical phenomena and transformations.

Energy can exist in various forms, including:

Kinetic Energy (KE): Energy of an object in motion.
Potential Energy (PE): Energy associated with an object's position or state.
Thermal (Heat) Energy: Energy associated with the temperature of an object.
Chemical Energy: Energy stored in chemical bonds.
Electrical Energy: Energy associated with the flow of electric charge.
Gravitational Potential Energy: Energy based on an object's height in a gravitational field.

Work done by a force can result in the transfer or conversion of energy.
The work-energy theorem states that the work done on an object is equal to the change in its kinetic energy:
- W = ΔKE
Where:
- W is the work done (in joules).
- ΔKE is the change in kinetic energy (in joules).

The law of conservation of energy states that energy cannot be created or destroyed; it can only change from one form to another.
This principle is fundamental in understanding energy transformations and is a cornerstone of physics.

Work done by a force is calculated using the formula:
- W = F * d
Where:
- W is the work done (in joules).
- F is the force applied (in newtons).
- d is the distance over which the force is applied (in meters).
To calculate potential energy, the formula is often used:
- PE = m * g * h
Where:
- PE is the potential energy (in joules).
- m is the mass of the object (in kilograms).
- g is the acceleration due to gravity (approximately 9.81 m/s²).
- h is the height above a reference point (in meters).

Energy can be transformed from one form to another. For example:
- When an object falls, potential energy is converted into kinetic energy.
- When a car brakes, kinetic energy is converted into thermal energy due to friction.

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Summary

Energy is the capacity to do work or produce an effect and can exist in various forms.
The work-energy theorem relates work done to the change in kinetic energy.
The law of conservation of energy states that energy is conserved and cannot be created or destroyed, only transformed.
Energy calculations involve formulas for work, kinetic energy, and potential energy.
Understanding energy transformations is crucial in explaining physical phenomena.

Energy diagram

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