To demonstrate Interconversion of Potential and Kinetic Energy

Objective

To demonstrate interconversion of potential and kinetic energy.

 

Theory  

Energy is the ability to do work or cause change. Energy comes in two basic types: kinetic energy and potential energy. Kinetic energy is a measure of work an object can do by virtue of its motion. It depends on the mass and velocity of the object. Potential energy is the energy that results from the position of an object. 

Mechanical energy is the sum of the kinetic and potential energies in a system. The principle of the conservation of energy states that the total mechanical energy in a system is the sum of the potential and the kinetic energies that remain constant if the forces acting are conservative forces. 

 

How are Potential and Kinetic Energy Related? 
When an object moves, potential energy transforms into kinetic energy. An object at rest has potential energy but no kinetic energy. Mechanical energy refers to the sum of both kinetic and potential energy.  

  • In the experiment, the wheel gains some potential energy as it rises. When released, it falls, and its potential energy is changed into the kinetic energy of the wheel's rotation.  
  • When the wheel reaches its lowest position, the potential energy becomes zero. The kinetic energy of the wheel reaches its maximum.  
  • Due to this, the kinetic energy thread starts winding up in the opposite direction. 
  • When the wheel rises, kinetic energy is converted to potential energy. 
  • Maxwell's wheel is used to demonstrate the conservation of energy. 
  • Each time the wheel is wound back up the string, it loses height due to friction loss. 

                                                            

                                                                                                                       Fig:1  Maxwell's wheel 

 

Interconversion of potential energy and kinetic energy in a simple pendulum 

                                                                   

                                                                                                               Fig.2: Simple pendulum 

  • A simple pendulum demonstrates the conservation of mechanical energy. 
  • The kinetic energy and potential energy of the system vary continuously during one full cycle of motion. However, in the case of a simple pendulum, the sum of its potential and kinetic energy remains constant. 
  • At the lowest position (B) of the simple pendulum, kinetic energy is at its maximum. In this position, all the energy is kinetic energy. 
  • At the highest positions (A and C) of the simple pendulum, potential energy is at its maximum. In this position, all the energy is potential energy. 
  • If there is any frictional force or any drag force due to air, total mechanical energy will not be constant. The pendulum would come to rest eventually. 

 

Learning Outcomes 

Students  

  • Understand the concept of energy conservation. 
  • Comprehend the two types of energy and how they act. 
  • Demonstrate the conservation of mechanical energy concepts.