1. Ch 8 Average Velocity wkst 2 uniform motion

2. 1. What would happen if you put on ice skates and gave yourself a push off the boards in terms of motion and speed?
Glide across the ice but eventually slow down and stop.

3. 2. What causes you to stop in question 1?
Friction between ice and skates. Maybe some air resistance. We shall look at that more in ch 9.

4. You would never stop. You would be in uniform (unchanging) motion.
3. What would happen if there was no friction when you pushed yourself on the ice now?
You would never stop. You would be in uniform (unchanging) motion.

5. 4. Define uniform motion.
Travelling in equal displacements in equal time intervals; neither speeding up, slowing down nor changing direction.

6. 5. Does true uniform motion exist in the physical world around you?NO
There are examples that are close.
Applying a uniform motion model to those situations can help us understand motion in the real world.

7. 6. What is a motion diagram?
A diagram that shows an object’s position at given times and allows us to picture or visualize motion.

8. 7. What is the horizontal axis on a graph called?
X axis
What is the vertical axis on a graph called?
Y axis

9. 9. What is a position-time graph and what units go on the graph axes?
A graph that has time on the x axis and position data on the y axis. A graph of the object’s position at various time intervals.

10. 10. Sketch fig 8.10, the motion diagram, with the ball rolling at various time intervals.

13. 12. Uniform motion is represented by a ____ on a position time graph.
STRAIGHT LINE

14. 13. Why is real motion not perfectly uniform?
There may be measuring errors, bumps and dents on surfaces when doing experiments, etc.

15. 14. What is a best-fit line for graphing?
It is a smooth curve or straight line that most closely fits the general shape outlined by the points on a graph.

16. 15. What can the position-time graphs be used for?
Estimate positions and times that are not given as data. Can also be extended beyond the data points to estimate.

17. 16. Use the graph on page 351 to estimate the position of the ball at:
16. Use the graph on page 351 to estimate the position of the ball at: a s _____________ b s _____________

19. 16. Use the graph on page 351 to estimate the position of the ball at:
16. Use the graph on page 351 to estimate the position of the ball at: a s _____________ b s _____________
70 cm [right]
90 cm [right]

20. Extension: Use the graph on page 351 to estimate the time at 50 cm?

22. Extension: Use the graph on page 351 to estimate the time at 50 cm?

23. 17. Define slope of a graph.
Refers to whether the line on a graph is horizontal, or goes up or down at an angle. You can also tell how much of an angle it is going up or down. ( steep or gradual slope)

24. 18. What are the 3 kinds of slopes that a graph can have?
Positive, zero, or negative.

25. The objects are moving in opposite directions.
19. On a position-time graph, compare objects whose data produce positive slopes vs objects with whose data produce negative slopes.
The objects are moving in opposite directions.

26. 20. Describe a positive slope and what is happening to the moving object. Sketch the example graph of a moving object whose data produces a graph with positive slope.
Positive slope slants up to the right. The object’s position is going further away from the origin or starting point.

28. 21. Describe a graph with a line that has zero slope and what is happening to the motion of an object that has zero slope. Sketch the example graph of an object whose data produces a graph with zero slope.
Graph has a line that is horizontal. The object is at rest or not moving. This is still uniform motion as the displacement of the object is 0 m for any time interval.

30. 22. Describe a graph with negative slope
22. Describe a graph with negative slope. What is happening to an object that produces a graph with negative slope? Sketch the example graph of an object whose data produces a graph with negative slope.
The line slopes down to the right. The object is travelling towards the origin or starting point.

32. Negative slope = travelling towards the origin
with uniform motion
Here we are at the origin
Now we passed
the origin and are
moving away with uniform motion