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Distance and displacement

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- 1. OBJECTS IN MOTION. 01. Distance and displacement. Ian Anderson Saint Ignatius College Geelong
- 2. DISTANCE V DISPLACEMENT. How far do you think you walk every day while at school between homeroom in the morning and homeroom in the afternoon?
- 3. DISTANCE V DISPLACEMENT. What would you say if I said you walked 0 m? It’s true! Your displacement between morning homeroom and afternoon homeroom is zero. Although the distance you walked is probably closer to around 2500 m. So what is the difference between distance and displacement?
- 4. DISTANCE V DISPLACEMENT. Follow the clues on the treasure map to find the buried treasure. Source: Sharwood (2006)
- 5. DISTANCE V DISPLACEMENT. How many paces have you walked when you get to the treasure? Answer = 3200 paces. Source: Sharwood (2006) How many paces are you actually away from your landing point? Answer = 200 paces to the west.
- 6. DISTANCE V DISPLACEMENT. How many paces have you walked when you get to the treasure? Answer = 3200 paces. How many paces are you actually away from your landing point? Answer = 200 paces to the west. Source: Sharwood (2006)
- 7. DISTANCE. Distance is a measure of how far an object travels over a certain period of time. 3200 paces in our pirate treasure example. Distance can be measured in any length units, including kilometres or millimetres, but is usually converted into metres. Metres (m) is the SI unit for distance. Distance is a scalar quantity because it only has size but no direction.
- 8. DISPLACEMENT. Displacement describes the change in position of an object and its direction over a certain period of time. It is the shortest distance between the initial point and the final point. 200 paces West in our pirate treasure example. The SI unit for displacement is metres (m). The direction of the change in position can be described using compass points (N, S, E or W); left or right; or positive (+) or negative (-). Displacement is a vector quantity because it has size and direction.
- 9. POSITION-TIME GRAPHS. Position-time graphs (also called displacement-time graphs) show the total distance travelled by an object over time. Position-time graphs can be used to determine The displacement of an object at any point in time. The speed or velocity of an object at any point in time.
- 10. POSITION-TIME GRAPHS. Position-time graphs (also called displacement-time graphs) show the total distance travelled by an object over time. Position-time graphs can be used to determine The displacement of an object at any point in time. The speed or velocity of an object at any point in time.
- 11. POSITION-TIME GRAPHS. Position-time graphs show the total distance covered by an object as time progressed. The object first covers a distance of 4 m in 6 s, stops for 2 s, before setting off again for a distance of 8 m in 4 s, before finally resting for another 3 s. The total distance covered was 12 m. Source: Alford et al. (2010)
- 12. POSITION-TIME GRAPHS. Position-time graphs can also be used to determine the displacement of an object at any point in time. At 6 s the displacement of the object is 4 m N (or +4 m). The displacement of the object at the end of the journey is 4 m S (or -4 m). Source: Alford et al. (2010)
- 13. POSITION-TIME GRAPHS. Use the position-time graph to answer the questions that follow. Source: Sharwood et al. (2006)
- 14. POSITION-TIME GRAPHS. 1. At what time/s was the object stationary? Answer = Between 0 & 30 s and again between 60 & 80 s. Source: Sharwood et al. (2006)
- 15. POSITION-TIME GRAPHS. 2. What was the objects distance from it’s starting point at t=60 s? Answer = 60 m Note: At 60 s the object’s displacement is -20 m from point (P). Source: Sharwood et al. (2006)
- 16. POSITION-TIME GRAPHS. 3. What was the objects displacement from it’s starting point at t=60 s? Answer = 60 m S Source: Sharwood et al. (2006)
- 17. BIBLIOGRAPHY. Alford, K., Keenihan, S., Malone, J., & Smart, A. (2010). Big Ideas Science 3: VELS Edition. Melbourne: Oxford University Press. Sharwood, J. (Ed.). (2006). Science Edge 4. Melbourne: Thomson Learning.