1. Warm-Up 9/24/13
Look in your group’s folder for a set of distance vs. time graphs.
For each graph, calculate the slope of the line. The slope represents the car’s speed!
Based on your calculations, write an equation for speed.
𝑆𝑝𝑒𝑒𝑑= ? ?

2. Speed and Velocity
Section 11.2
Tuesday 9/24/13

3. Speed A scalar quantity (amount, no direction)
Typically reported as m/s

4. Measuring Speed Average Speed is calculated for an entire trip
= 𝑇𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑇𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒
Instantaneous Speed is calculated at a particular instant
= 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑇𝑖𝑚𝑒

5. Example
Calculate the average speed of a runner that covers 50km in 15s, and slows to cover the second 50km in 20s.
What is the instantaneous speed if at 10s the runner has gone 35m?

6. Distance-Time Graphs
Distance-Time graphs make calculating velocity easy!
𝑺𝒍𝒐𝒑𝒆= 𝑟𝑖𝑠𝑒 𝑟𝑢𝑛
= 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑇𝑖𝑚𝑒

7. Changing Speeds
How can a graph represent changing speeds during a trip?

8. Displacement-Time Graphs
We can also graph displacement.
This will show us if someone ever turned around and travelled back to the origin!

9. Velocity A vector quantity (amount and direction)
Velocity describes both speed AND direction of motion.

10. Changing Velocity
Velocity changes with a change in speed, change in direction, or both!
Golf club slows (changes in speed) and changes direction!

11. Your Job
Work on the Graph Matching Activity. Match a graph to a description, and glue both down to the plain sheet of paper
DUE TOMORROW: Edible Car Lab questions