2. Unit B 1.1 Motion

3. Motion Motion is when an object moves a distance. Uniform Motion: describes an object that is travelling at a constant rate of motion in a straight line. – It is nearly impossible to achieve uniform motion in our everyday lives – Even driving with cruise control on a straight highway there are factors which slow and speed the car up... Wind resistance, friction of the tires on the road, which make the engine work harder varying the rate of motion slightly.

4. Speed Average speed: uniform motion that involves travelling a distance in a specified time. – The term average speed is used because uniform motion is hard to maintain. Average Speed = total distance travelled total time elapsed v = d total distance = d 1 + d 2 t

5. Speed Example A person walks 10.0m away from a stop sign in 5.00s. What is the average speed of the person? d = 10 m t = 5 s v = ? v = d/t v = 10m/5s v = 2.00 m/s The person walked at a speed of 2.00 m/s

6. Example A huge ocean wave travels a distance of 4.0 x 10 6 m in 3.6 x 10 4 s. Calculate the average speed of the ocean wave? d = 4.0 x 10 6 m t = 3.6 x 10 4 s v = ? v = d/t v = 4.0 x 10 6 m / 3.6 x 10 4 s v = 111.11 m/s The wave travels at 1.1 x 10 2 m/s

7. Example A Concorde airplane could fly at an average speed of 694 m/s. Calculated how long it would have taken the Concorde to fly around the world, which is approximately 4.00 x 10 7 m. d = 4.00 x 10 7 m t = ? v = 694 m/s v = d/t 694 m/s = 4.00 x 10 7 m / t t x 694 m/s = 4.00 x 10 7 m / t x t (t x 694 m/s) / 694m/s = 4.00 x 10 7 m / 694 m/s 5.76 x 10 4 s = t The time it took to fly around the world was 5.76 x 10 4 s

8. Example An electric train is travelling at an average speed of 6.9m/s for 4.0s. Calculate the distance travelled by the train. d = ? t = 4.0s v = 6.9m/s v = d/t 6.9m/s = d / 4.0s 6.9 m/s (4.0s) = d 27.6 m = d The distance travelled by the train is 28m.

9. Distance Time Graphs The relationship between the distance travelled by an object in and the to the time it took for the object to travel that distance. A line of best fit is used to indicate the direct LINEAR relationship between distance and time. The SLOPE of the line determines the AVERAGE SPEED travelled. The greater or more vertical the slope, indicates a faster speed and a more horizontal slope indicates a slower speed.

10. Plotting Distance Time Graphs When graphing – Use a pencil – Use a ruler – Make sure your graph has a title – Equal intervals – Label the axis with units – Manipulated variable on the x-axis – Responding variable on the y-axis

11. Graph the following information. (don’t forget to label the axis and provide a title) Time (s)Distance from First Marker (m) 0.00 2.010 4.020 6.030 8.040 10.050

13. Look at the slope of the line. Slope = Rise / Run Slope = change in y / change in x Slope = change in distance / change in time Slope = Speed For the graph Slope = Rise / Run Slope = 30m - 10m / 6s - 2s Slope = 20m / 4s Slope = 5 m/s Therefore the average speed, v, is 5.0m/s

14. A Speed-Time Graph A speed - time graph describes the motion of an object. The line of best fit is a straight line, indicating a linear relationship between the speed of the object and the time elapsed. When the line is horizontal, it means that as the time elapsed increases, the speed remains constant, therefore uniform motion. Double check that it is uniform motion by calculating the slope. If the Slope = 0 m/s, then uniform motion has been reached. Slope = rise/run

15. The distance travelled can be determined by calculating the area under the line of the graph. – Area under the line = area of a rectangle – A = length x width – A = (v)(t) – Area = distance (m) Remember a line sloping upward = speeds increasing A line sloping downward = speeds decreasing

16. Graph the following information. (don’t forget to label the axis and provide a title) Time when boat passes marker (s) Speed of the boat as it passes each marker(m/ s) 0.05.00 2.05.00 4.05.00 6.05.00 8.05.00 10.05.00

17. What is the slope of this line ?? What does it mean ?

18. DESCRIBE THE MOTION LINE 1 LINE 2 LINE 3

19. m/s km/h 500m = ? km 40hr = ? mins = ? s 8.75km = ? m = ? cm 7923s = ? hr ***When doing calculations make sure you look at your units***

20. Homework Read Science 10 p. 127 – 135 Check and Reflect 1-13, 16-17, due the next day.