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GRAPHING MOTION. Distance vs. Time. GRAPHING MOTION. Describing a journey made by an object is very boring if you just use words. As with much of science, graphs are more revealing. Plotting distance against time can tell you a lot about a journey. GRAPHING MOTION. Let's look at the axes:.
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GRAPHING MOTION Distance vs. Time
GRAPHING MOTION • Describing a journey made by an object is very boring if you just use words. As with much of science, graphs are more revealing. • Plotting distance against time can tell you a lot about a journey.
GRAPHING MOTION • Let's look at the axes:
GRAPHING MOTION • Time always runs horizontally (the x-axis). The arrow shows the direction of time. The further to the right, the longer time from the start.
GRAPHING MOTION • Distance runs vertically (the y-axis). The higher up the graph we go, the further we are from the start.
GRAPHING MOTION • If something is not moving, a horizontal line is drawn on a distance-time graph. • Time is increasing to the right, but its distance does not change. • This graph shows an object that is stationary.
GRAPHING MOTION • If something is moving at a steady speed, it means we expect the same increase in distance in a given time. • Time is increasing to the right, and distance is increasing steadily with time.
GRAPHING MOTION • This graph shows an object that moves at a steady, constant speed.
GRAPHING MOTION • Both the lines below show that each object moved the same distance, but the steeper yellow line got there before the other one. • What does this indicate?
GRAPHING MOTION • A steeper slope indicates a larger distance moved in a given time. In other words, higher speed. • This is shown in yellow.
GRAPHING MOTION • Yellow: speed = distance / time = 30 m / 10 s =3 m/s • Blue: speed = distance / time = 20 m / 20 s =1 m/s
GRAPHING MOTION • For the first part of the journey shown by the graph below, the object moved at a steady (slow) speed.
GRAPHING MOTION • Then the object suddenly increased its speed, covering a much larger distance in the same time. • The speed increased in the second part of the journey.
GRAPHING MOTION • The line below is curving upwards. This shows an increase in speed, since the slope is getting steeper over time.
GRAPHING MOTION • In other words, in a given time, the distance the object moves is larger. • It is accelerating.
GRAPHING MOTION • There are three parts to the journey shown here… Where is the graph showing motion that is: • Stopped? • Moving at a quick constant speed? • Traveling at a slow constant speed? C B A
GRAPHING MOTION • The graph below shows several stages of motion: Stage 1:100 m in 10 s. Stage 2:50 m in 10 s. Stage 3:150 m in 20 s. Calculate the speeds of each stage, indicated by the colors.
GRAPHING MOTION • The graph below shows several stages of motion: Stage 1:speed = distance / time = 100 m / 10 s =10 m/s Stage 2:speed = distance / time = 50 m / 10 s =5 m/s Stage 3:speed = distance / time = 150 m / 20 s =7.5 m/s.
GRAPHING MOTION • The graph below shows several stages of motion: Stage 1:constant speed at a relatively high rate Stage 2:constant speed at a relatively slow rate Stage 3:constant speedat a “medium” rate (between the others)
GRAPHING MOTION • The graph below shows several stages of motion: The slope of the line (its steepness) indicates rate of change of position. Speed can be estimated by the slope of the line… faster, slower, etc.
GRAPHING MOTION • Distance vs. time graphs also indicate the position of the object. Stage 1&Stage 2:object is moving away from the starting point Stage 3:object is moving back toward the starting point (it comes back to zero)
GRAPHING MOTION • The steeper the line on a distance vs. time graph, the faster the object’s speed. • A curved line indicates a change in speed (accelerating or decelerating).
GRAPHING MOTION • Lines pointing up indicate moving away from the starting location. • Lines pointing down indicate moving back towards the starting location.
GRAPHING MOTION • Let’s see how much this makes sense to you… • This is not for a grade, just to let me know how much of this and what parts of it you “get.”
GRAPHING MOTION • To learn about speed vs. time graphs, visit this link: http://www.gcse.com/fm/stg.htm