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# Unit 4: Work, energy and power (Hindi)

"Energy" is a word that's used a lot. Here, you'll learn about how it's one of the most useful concepts in physics. Along the way, we'll talk about work, kinetic energy, potential energy, and conservation of energy.

## Introduction to work (Hindi)

You're doing a lot more work than you realize (most of which goes unpaid). This lesson will introduce the definition of work we use in physics, which will give us another way to think about forces and movement.

## Kinetic energy (Hindi)

Kinetic energy is the energy an object has because of its motion. We'll talk about how to calculate kinetic energy, and how kinetic energy is related to work.

## Gravitational potential energy and conservative forces (Hindi)

Learn about what gravitational energy means and how it is related to conservative forces such as gravity.

## Spring potential energy and Hooke's law (Hindi)

Weighing machines of all sorts employ springs that take a certain amount of force to keep compressed or stretched to a certain point. Hooke's law will give us all the tools to weigh in on the subject ourselves and spring into action (pun intended)!

## Conservation of energy (Hindi)

Learn about the law of conservation of energy, and how it can be useful for solving physics problems.

## Power (Hindi)

Learn what power means and how we use it in physics to describe the rate of energy transfer.

## Elastic and inelastic collisions (Hindi)

Categorizing the different types of collisions can be useful. Here, you'll learn what it means for a collision to be elastic or inelastic and what that implies mathematically.