1. Calculating Speed/Velocity & Using Motion Graphs Chapter 9.2 & 1. 5 The meaning of miles per hour

2. I. Calculating Speed & Velocity  In other words, you need a formula Speed/Velocity Formula: speed = distance ÷ time Or speed = distance/time To calculate the speed of an object, divide the distance the object travels by the amount of time it takes to travel that distance. Velocity = speed in a given direction

3. Instantaneous Speed Examples - Average Speed Examples -

4. I. Calculating Speed/Velocity Because most object do not travel at a constant speed or velocity, we usually calculate the average speed. Average speed equals the total distance traveled divided by the total time of the trip. Or

6. V ave = 100 mi = 33.33 mi/hr 3 hrs

7. II. What else can we calculate with this formula? Distance – if you know the average speed and how much time you have, you can calculate how far something will travel. Distance = Speed x Time

9. Distance = speed X time D = (12 mi )(.3 hr) hr D = 3.6 mi

10. III. One more thing we can calculate with the formula Time – if you know average speed and have a known distance, you can calculate how long it will take to get there. Time = Distance/Speed How long will it take to run 6 km if your average running speed is 4 km/hr? Time = 6km 4km/hr Time = 1.5 hrs

11. IV. An Easy Way to Remember the Formulas The Magic Triangle! D ST S T Cover up the variable you are solving for. The other 2 are in the right position for the formula.

12. V. Plotting a Line Graph Chapter 1 Introduction to Physical Science * Write the 6 steps

13. VI. Slope The slope of a graph line tells you how much y changes for every change in x. Chapter 1 Introduction to Physical Science Slope = rise/run Slope = (y 2 – y 1 )/ (x 2 – X 1 ) For distance vs. time problems, slope = average speed

14. VII. Using Graphs to Identify Trends Chapter 1 Introduction to Physical Science Line graphs are powerful tools in science because they allow you to identify trends and make predictions. On a distance vs. time graph you can use the slope to find the speed at different time intervals and average speed for the whole trip.

15. Graphing Motion You can use distance-versus-time graphs to interpret motion. Chapter 9 Motion and Energy