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<math>R</math> = The [[Electrical Resistance|resistance]] of the [[Electrical Component|component]].
===Example Calculations===
{| class="wikitable"
| style="height:20px; width:200px; text-align:center;" |A piano falls down a flight of stairs. In this fall 5.4kJ of [[energy]] is [[Energy Transfer|transferred]] from the [[Gravitational Potential Energy Store|gravitational potential energy store]] into the [[Kinetic Energy Store|kinetic energy store]] of the piano. It take 0.80 seconds to reach the bottom of the stairs. Calculate the average '''power''' of this transfer correct to two [[Significant Figures|significant figures]].
| style="height:20px; width:200px; text-align:center;" |A '[[weight]] lifter' lifts a 2000N [[weight]] a distance of 1.2 [[metre]] from its original position. They do this in 0.70 [[second]]s. Calculate the [[power]] output of the '[[weight]] lifter' correct to two [[Significant Figures|significant figures]].
|-
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
W = 5.4kJ = 5400J
t = 0.80s
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
F = 2000N
d = 1.2m
t = 0.70s
|-
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>P = \frac{W}{t}</math>
<math>P = \frac{5400}{0.80}</math>
<math>P = 6750W</math>
<math>P \approx 6800W</math>
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>W = \vec F \vec d</math>
<math>W = \vec F \times \vec d</math>
<math>W = 2000 \times 1.2</math>
<math>W = 2400J</math>
<math>P = \frac{W}{t}</math>
<math>P = \frac{2400}{0.7}</math>
<math>P = 3428.57W</math>
<math>P \approx 3400W</math>
|}