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<math>Speed = 50m/s </math>
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{| class="wikitable"
| style="height:20px; width:300px; text-align:center;" |'''A [[horse]] takes 20 [[minute]]s to trot 2.4 [[kilometre]]s. Calculate the speed of the [[horse]] in [[Metres per second|metres per second]].'''
| style="height:20px; width:300px; text-align:center;" |'''The International Space Station takes 92 [[minute]]s to orbit the Earth once travelling 42,000 [[kilometre]]s. Calculate the speed of the ISS.'''
|-
| style="height:20px; width:300px; text-align:left;" |
distance = 2.4[[km]] = 2400[[m]]
time = 20[[min]] = 1200[[s]]
<math>Speed = {\frac{distance}{time}} </math>
<math>Speed = {\frac{2400}{1200}} </math>
<math>Speed = 2m/s </math>
| style="height:20px; width:300px; text-align:left;" |
distance = 42,000[[km]] = 42,000,000[[m]]
time = 20[[min]] = 5400[[s]]
<math>Speed = {\frac{distance}{time}} </math>
<math>Speed = {\frac{42000000}{5400}} </math>
<math>Speed = 7608.7m/s </math>
<math>Speed \approx 7600m/s </math>
|}
==Key Stage 4==
===Meaning===
[[Speed]] is a [[scalar]] quantity which describes the rate at which an [[object]] changes position.
===About Speed===
: [[Speed]] is a [[scalar]] because it has only [[magnitude]] but no direction.
: The [[SI Unit]]s of [[speed]] are [[Metres per Second]].
: [[Speed]] is commonly measured in the [[unit]]s of [[Miles per Hour]], but this is not a scientific [[unit]].
: Other [[unit]]s of [[speed]] can be given by the [[unit]]s of [[distance]] used and the [[unit]]s of [[time]] used in the calculation of [[speed]]. If [[centimetre]]s and [[minute]]s are used then the [[unit]]s of [[speed]] would be centimetres per minute.
: [[Speed]] can be found by [[measuring]] the [[distance]] travelled by an [[object]] in a given [[time]].
===Equation===
:<math>Speed = {\frac{distance}{time}} </math>
:<math>s = \frac{D}{t} </math>
Where:
: s = [[Speed]]
: D = [[Distance]]
: t = [[Time]]
===Example Calculations===
{| class="wikitable"
|-
| style="height:20px; width:300px; text-align:center;" |A person jogs 315 [[metre]]s in 120 [[second]]s. Calculate the [[speed]] of the jogger correct to two [[Significant Figures|significant figures]].
| style="height:20px; width:300px; text-align:center;" |A racing car travels 0.59km in 14 [[second]]s. Calculate the speed of the racing car correct to two [[Significant Figures|significant figures]].
|-
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
distance = 315m
time = 120s
| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities'''
distance = 0.59km = 590m
time = 14s
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>s = {\frac{D}{t}} </math>
<math>s = {\frac{315}{120}} </math>
<math>s = 2.625m/s </math>
<math>s \approx 2.6m/s</math>
| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>s = {\frac{D}{t}} </math>
<math>s = {\frac{590}{14}} </math>
<math>s = 42.142857m/s </math>
<math>s \approx 42m/s</math>
|}