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→Calculating Velocity from Kinetic Energy
{| class="wikitable"
| style="height:20px; width:200px; text-align:center;" |A 75kg person has a '''kinetic energy''' of 96J while while walking. Calculate their [[speed]].
| style="height:20px; width:200px; text-align:center;" |QuestionA [[bird]] of [[mass]] 2.4kg flies at a constant [[speed]] with a '''kinetic energy store''' of 1500J. Calculate the [[speed]] of the [[bird]] correct to two [[Significant Figure|significant figures]].
| style="height:20px; width:200px; text-align:center;" |Question
|-
m = 75kg
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
E<sub>k</sub> = 1500J
m = 2.4kg
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
|-
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
<math>E_k = \frac{1}{2} m v^2</math>
<math>1500 = \frac{1}{2} \times 2.4 \times v^2</math>
<math>1500 = 1.2v^2</math>
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers and [[Evaluate (Maths)|evaluate]].'''
|-
| style="height:20px; width:200px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
<math>v^2 = \frac{1500}{1.2}</math>
<math>v = \sqrt{\frac{1500}{1.2}}</math>
<math>v = 35.35534m/s</math>
<math>v \approx 35m/s</math>
| style="height:20px; width:200px; text-align:left;" |'''3. [[Rearrange (Maths)|Rearrange]] the equation and [[Solve (Maths)|solve]].'''
|}