## October 4, 2011

### Energy Formulae summary

Here is a list of all the formula mentioned in this topic:

$Efficiency=\frac{Useful\: Energy\: output}{Total\: Energy\: input} \left (\times 100 \right )$

$Wd=F\times d$

$GPE=mgh$

$KE=\frac{mv^{2}}{2}$

$P=\frac{E}{t}\: or\: \frac{Wd}{t}$

$Total\: Energy\: output=Total\: Energy\: input$

Quantities and Units
• Energy = Joules (J)
• Wd = Work done (J)
• GPE = Gravitational Potential Energy (J)
• KE = Kinetic Energy (J)
• F = force (N, Newtons)
• d = distance moved in the direction of the force (m, metres)
• m = mass (kg)
• g = gravitational field strength (N/kg) NB: G on earth = 10N/kg
• h = height (m)
• v = velocity (m/s)
• P = power (W, Watts)
• t = time (s)
End of Energy Topic