1 / 22

Distance & Displacement

Distance & Displacement. Distance is a Scalar. A measure of the length of a path an object takes in moving from one position to another is called distance. Distance is how far an object has moved Distance is a scalar quantity. . 0. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. cm.

bertha
Download Presentation

Distance & Displacement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Distance & Displacement

  2. Distance is a Scalar • A measure of the length of a path an object takes in moving from one position to another is called distance. • Distance is how far an object has moved • Distance is a scalar quantity.

  3. 0 1 2 3 4 5 6 7 8 9 10 cm Distance • Distance (d) = how far an object travels. • Does not depend on direction. • Imagine an ant crawling along a ruler. • What distance did the ant travel? d = 3 cm

  4. 0 1 2 3 4 5 6 7 8 9 10 cm Distance • Distance does not depend on direction. • Now what distance did the ant travel? d = 3 cm

  5. 0 1 2 3 4 5 6 7 8 9 10 cm Distance • Distance does not depend on direction. • Follow the ant again: • What distance did the ant walk this time? • d = 7 cm

  6. Displacement is a Vector • Displacement is the change in position of an object and includes a description of the direction of motion. • Determined by drawing a straight line from starting position to ending position • Is not always equal to distance traveled.

  7. Displacement

  8. - + 0 1 2 3 4 5 6 7 8 9 10 cm Displacement • Displacement has direction. • Distance: 3 cm • Displacement: +3 cm The positive gives the ant a direction

  9. - + 0 1 2 3 4 5 6 7 8 9 10 cm Displacement • Find the ant’s displacement again. • Distance: 3 cm • Displacement: -3 cm

  10. - + 0 1 2 3 4 5 6 7 8 9 10 cm Displacement • Find the distance and displacement of the ant. • Distance: 7 cm • Displacement: +3 cm • = 5cm – 2cm = +3cm

  11. QUESTION: How far (in km) will a car travel in 15 min at 20 m/s ? d = s x t = (20 m) x (60 s)  (15 min) s min = 18 000 m (divide 1000 for km) = 18 km

  12. Displacement E.g. the distance travelled here by a driver was 14.5 km even though the displacement was only 2.7 km [North].

  13. E.g If a person travels 40m east, turns and travels 30m west, the displacement of the person is 10m east. • If a person travels 40m east and then travels another 50m east, the displacement is 90m east.

  14. Displacement Example: Mandisawalks 2 m [East] and then 1 m [West]. What was her distance travelled? What was her displacement? Distance travelled: Dd = 2 m + 1 m = 3 m Displacement: She is 1 m [East] of her original starting position. 1 m 1 m

  15. Displacement 2 m We can represent [East] as the positive direction and [West] as the negative direction: = 2 m [East] + 1 m [West] = + 2 m – 1 m = + 1 m = 1 m [East] 1 m 1 m

  16. What is the difference between distance and displacement? Distance: How far something travels Displacement: How far something travels in a given direction in a straight line from start to finish.

  17. A soccer player changes position back and forth on the field. In the diagram below each position is marked where the player reverses direction. The player moves from position A to B to C to D. • Find the distance and displacement of travel.

  18. Solution: Distance = 85 m Displacement = 55 m left of A

  19. Displacement • Therefore, displacement =difference between an object’s final position and its starting position. • Does depend on direction. • Displacement = final position – initial position • Examples of directions: • + and – • N, S, E, W • Angles

  20. Displacement vs. Distance • Example of distance: • The car drove 30 km. • Example of displacement: • The car drove 30 km. EAST. • An object’s distance traveled and its displacement aren’t always the same!

  21. An athlete runs around a track that is 100 meters long three times, then stops. What is the athlete’s distance and displacement? Distance = 300 m Displacement = 0 m Why? Displacement vs. Distance

  22. Complete worksheet

More Related