Physics Notes Sheets: Energy, Conservation of Energy, and Power

Key Definitions

• Energy: The capacity to do work or cause change in a system

• Work: Force applied over a distance (W = F x d)

• Power: Rate of doing work or transferring energy (P = W / t)

• Potential Energy (GPE): Stored energy due to position or configuration

• Kinetic Energy (KE): Energy of motion

Types of Energy

1. Mechanical Energy

   • Potential Energy (PE)

     • Gravitation PE: mgh (mass x gravity x height)

   • Kinetic Energy (KE): ½ mv² (mass x velocity²)

2. Other Energy FormS

   • Thermal Energy

   • Chemical Energy

   • Electrical Energy

   • Nuclear Energy

Conservation of Energy Principle

• Total Energy in a Closed System Remains Constant

• Energy can transform between different forms

• Formula: Total Energy = GPE + KE + Other Energy Forms

• No energy is created or destroyed, only converted

Power Calculations

• Power (P): Work done per unit time

• Units: Watts (W) = Joules/second (J/s)

• Formulas:

  • P = W / T

  • P = F x v (Force x velocity)

Key Equations

1. Kinetic Energy: KE = ½mv²

2. Gravitational PE: PE = mgh

3. Power: P = W / t

Important Concepts

• Energy is always conserved in a closed system

• Energy can be transformed between different forms

Practical Examples

• Roller coaster: Conversion of GPE to KE

• Pendulum: Continous energy transformation

• Hydroelectric dam: GPE to electrical energy