Relationship between work and energy

Work and energy are closely related concepts in physics. Here’s how they are connected:

1. Work as a Transfer of Energy:
   • When work is done on an object, energy is transferred to or from that object. For instance, when you lift a book, you are doing work against gravity, and this work transfers energy to the book, increasing its gravitational potential energy.
2. Work-Energy Theorem:
   • The work-energy theorem states that the work done on an object is equal to the change in its kinetic energy. This means if you apply a force to move an object, the energy used to move it (work) changes the object’s energy (like speeding it up or slowing it down).
3. Types of Energy:
   • Work can transfer energy in various forms, such as kinetic energy (energy of motion), potential energy (stored energy due to position), thermal energy (heat), and more. For example, when you push a sled up a hill, you are converting your muscular energy (chemical energy) into the sled’s gravitational potential energy.
4. Conservation of Energy:
   • The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or converted from one form to another. When work is done, it transforms energy from one form to another. For example, in a car engine, the chemical energy in fuel is converted to kinetic energy (motion) through the work done by the engine.

Mathematically, Work done can also be represented as the change in energy (ΔE) of an object:

Example: 

• Lifting a book : picking it from the ground to put it on a shelf will Increase the book’s gravitational potential energy.

Dropping the Book: Gravity does work on it, converting potential energy into kinetic energy.