Changes

: A '''distance time graph ''' can show be used to calculate the [[speed]] of an [[object]].

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: distance = 400[[m]]400m: time = 80[[s]]80s:<math>Speed = {\tfracfrac{distance}{time}} </math>:<math>Speed = {\tfracfrac{400}{80}} </math>

: distance = 400[[m]]400m: time = 20[[s]]20s:<math>Speed = {\tfracfrac{distance}{time}} </math>:<math>Speed = {\tfracfrac{400}{20}} </math>

| style="height:20px; width:300px; text-align:left;" |'''Calculate the speed of the object between 20 and 80 seconds.''': distance = 100m: time = 60s:<math>Speed = {\frac{distance}{time}} </math>:<math>Speed = {\frac{100}{60}} </math>:<math>Speed \approx 1.7m/s </math>| style="height:20px; width:300px; text-align:left;" |'''Calculate the average speed of the object for its journey.''': distance = 500m: time = 80s:<math>Speed = {\frac{distance}{time}} </math>:<math>Speed = {\frac{500}{80}} </math>:<math>Speed = 6.25m/s </math>|} ==Key Stage 4=====Meaning===A '''distance time graph''' is a [[graph]] that shows how the [[distance]] of an [[object]] from the [[origin]] changes with [[time]]. ===About Distance Time Graphs===: '''Distance-time graphs''' give information about the journey taken by an [[object]].: On a '''distance time graph''' the [[distance]] is plotted on the [[y-axis]] and the [[mtime]]is plotted on the [[x-axis]].: A '''distance time graph''' can be used to calculate the [[speed]] of an [[object]].{| class= 60"wikitable"|-| style="height:20px; width:200px; text-align:center;" |'''Slow Speed'''| style="height:20px; width:200px; text-align:center;" |'''Medium Speed'''| style="height:20px; width:200px; text-align:center;" |'''High Speed'''|-|[[File:dtGraphSlowSpeed.png|center|200px]]|[[File:dtGraphMediumSpeed.png|center|200px]]|[[File:dtGraphHighSpeed.png|center|200px]]|-| style="height:20px; width:200px; text-align:center;" |A constant [[speed]] is shown by a constant positive [[gradient]].| style="height:20px; width:200px; text-align:center;" |A higher [[gradient]] means a higher [[speed]].| style="height:20px; width:200px; text-align:center;" |The highest [[speed]] is shown by the steepest [[gradient]].|-| style="height:20px; width:200px; text-align:center;" |'''Stationary'''| style="height:20px; width:200px; text-align:center;" |'''Accelerating'''| style="height:20px; width:200px; text-align:center;" |'''Decelerating'''|-|[[File:dtGraphStationary.png|center|200px]]|[[File:dtGraphAccelerating.png|center|200px]]|[[File:dtGraphDecelerating.png|center|200px]]|-| style="height:20px; width:200px; text-align:center;" |A [[gradient]] of zero shows the [[object]] is not moving.| style="height:20px; width:200px; text-align:center;" |[[Acceleration]] is shown by an increasing [[gradient]].| style="height:20px; width:200px; text-align:center;" |[[Deceleration]] is shown by a decreasing [[gradient]].|}  ===Example Calculations===: The speed can be calculated from a '''distance time graph''' by reading the graph and using the equation [[Speed=Distance/Time]].{| class="wikitable"|-|[[File:dtGraphCalculation4.png|center|300px]]|[[File:dtGraphCalculation5.png|center|300px]]|-| style="height:20px; width:300px; text-align:left;" |'''Calculate the [[speed]] of the object in the first 10 seconds of the journey.''': distance = 200m: time = 10s:<math>v= {\frac{distance}{time}} </math>:<math>Speed = {\frac{200}{10}} </math>:<math>Speed = 20m/s</math>| style="height:20px; width:300px; text-align:left;" |'''Calculate the [[speed]]of the object in the first 10 seconds of the journey.''': distance = 70m: time = 10s:<math>Speed = {\tfracfrac{distance}{time}} </math>:<math>Speed = {\tfracfrac{10070}{6010}} </math>:<math>Speed = 1.7m/s </math>|} {| class="wikitable"|-|[[File:dtGraphCalculation4.png|center|300px]]|[[File:dtGraphCalculation5.png|center|300px]]|-| style="height:20px; width:300px; text-align:centerleft;" |'''Calculate the average [[speed ]] of the [[object for its ]] over the entire journey.''': distance = 500[[m]]400m: time = 80s: <math>Speed= {\frac{distance}{time }} </math>:<math>Speed = {\frac{400}{80}} </math>:<math>Speed = 5m/s </math>| style="height:20px; width:300px; text-align:left;" |'''Calculate the average [[speed]] of the [[sobject]]over the entire journey.''': distance = 500m: time = 80s:<math>Speed = {\tfracfrac{distance}{time}} </math>:<math>Speed = {\tfracfrac{500}{80}} </math>