Energy

• Energy is the ability to do Work
• Law of Conservation of Energy

\begin{align}
W & =\vec{F}\cdot \vec{d} \
& =F_{x}(d) \
& =F\cos\Theta(d) \
& =Fd\cos\theta
\end

$$\$F_y\$doesnowork,sinceanglebetween\$F_y\$and\$d\$is90$$

• Energy is $Pt$ Power times time
• Watt hours exists

Types

• Kinetic Energy - moving
• Potential
  • Chemical
  • Electric Potential Energy
  • Magnetic
  • Gravity#Gravitational Potential Energy
  • Elastic
  • Springs
• Thermal Heat
• Light
• Sound
• Mechanical Energy

Efficiency

• Based on Law of Conservation of Energy
• Formula >> $\eta =\frac{E_{out}}{E_{in}}\times 100\mathrm{\%}$