Motion. Distance and Time Motion is described using words like distance, speed, time and...
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Transcript of Motion. Distance and Time Motion is described using words like distance, speed, time and...
![Page 1: Motion. Distance and Time Motion is described using words like distance, speed, time and acceleration. Time (t) is measured in seconds (s). A time of.](https://reader036.fdocuments.in/reader036/viewer/2022062301/56649ea05503460f94ba29ae/html5/thumbnails/1.jpg)
Motion
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Distance and Time
• Motion is described using words like distance, speed, time and acceleration.
• Time (t) is measured in seconds (s). A time of 14 seconds is written t = 14 s. Other units of time are minute (min) and hour (h).
![Page 3: Motion. Distance and Time Motion is described using words like distance, speed, time and acceleration. Time (t) is measured in seconds (s). A time of.](https://reader036.fdocuments.in/reader036/viewer/2022062301/56649ea05503460f94ba29ae/html5/thumbnails/3.jpg)
• Distance (d) is measured in metres (m). A distance of 28.5 metres is written d = 28.5 m. Other units of distance are cm and km.
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Speed
• The average speed (vav) for a journey is calculated from the distance travelled divided by the time taken to travel that distance:
Average Speed = distance travelled or vav = d
time taken t
![Page 5: Motion. Distance and Time Motion is described using words like distance, speed, time and acceleration. Time (t) is measured in seconds (s). A time of.](https://reader036.fdocuments.in/reader036/viewer/2022062301/56649ea05503460f94ba29ae/html5/thumbnails/5.jpg)
• Instantaneous speed is the actual speed at any moment.– Eg: the speedometer in a car measures the
instantaneous speed.
![Page 6: Motion. Distance and Time Motion is described using words like distance, speed, time and acceleration. Time (t) is measured in seconds (s). A time of.](https://reader036.fdocuments.in/reader036/viewer/2022062301/56649ea05503460f94ba29ae/html5/thumbnails/6.jpg)
• If the instantaneous speed does not change, then the speed is described as being constant, uniform or steady.
• Units of speed;Distance Unit Time Unit Speed Unit
centimetre cm second s centimetre per second cm s-1
metre m second s metre per second m s -1
kilometre km hour h kilometre per hour km h-1
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Formula
• When using a formula to make a calculation, always write down:– The formula being used.– A working step showing the numbers in the
calculation.– The answer with the correct units.
![Page 8: Motion. Distance and Time Motion is described using words like distance, speed, time and acceleration. Time (t) is measured in seconds (s). A time of.](https://reader036.fdocuments.in/reader036/viewer/2022062301/56649ea05503460f94ba29ae/html5/thumbnails/8.jpg)
How fast are you?• Go out on to the field.
Measure 10 metres and time how long it takes you to run/walk. Use a stopwatch and record your time.
• In class use the formula to work out your speed. Remember;Speed = distance/time
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Vav = d/t
• The above formula can be used to calculate;– The distance travelled, d,when v and t are known.– The time taken, t, when d and v are known.
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Examples
1.A car is travelling at a constant speed of 30 m s-1 . How far does it travel in 40 seconds?
2. A snail is moving along a cabbage leaf at 0.1 cm s-1. What time does it take to travel 3 cm?
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Solutions
1. d = vt= 30 x 40= 1200 m or (1.2 km)
2. t = d/v= 3/0.1= 30 s
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Exercises.• What is the length of the objects shown?
– A
– B
– C
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More Exercises
• Complete ‘Speedy Problems’ on page 9 and 10 of your workbook.