Jogger & Sprinter

1. Jogger & Sprinter • The diagram below shows a jogger and a sprinter running across the same field. • The sprinter starts running when the jogger reaches the 30 yard marker. • Each picture of the sprinter shows that two seconds have passed on your stopwatch.

2. Question #1 • When (time)and where do you think the 2 people are traveling at the same speed? Explain your answer. • Where (position) is each person when the two (2) people have the same speed?

3. When (time) do you think the 2 people are traveling the same speed? 32 • 0-2 seconds • 2-4 seconds • 4-6 seconds • 6-8 seconds 0 0 0 0 0 10 Countdown

4. Where (position) is each person when the two (2) people have the same speed? 32 • Sprinter and jogger at 30 yard line • Sprinter at 35 yd line; jogger at 40 yd line • Sprinter at 45 yard line; jogger at 50 yd line • Sprinter and jogger at 60 yd line • Sprinter at 75 yard line; jogger at 70 yd line 0 0 0 0 0 0 10 Countdown

5. Why is that?

6. Journal CH 3.1Average Speed

7. Performance Expectations (PS1A) • Identify or calculate an object’s average speed given distance traveled over an interval of time, using S = d/t (e.g., a battery-powered toy car travels 20meters in 5 seconds, so its average speed is 4 meters per second). • Describe the motion of an object based on a graph of the object’s position vs. time. • Identify the position vs. time graph that could represent an object’s motion given average speed or position and time data of that object.

8. Average Speed • Average Speed = Distance Traveled Time Taken

9. Calculate the speed for each section 10 yards 2 sec = 5 yds/sec 10 yards 2 sec = 5 yds/sec 10 yards 2 sec = 5 yds/sec 10 yards 2 sec = 5 yds/sec • Average Speed = Distance Traveled Time Taken 15 yards 2 sec = 7.5 yds/sec 10 yards 2 sec = 5 yds/sec 15 yards 2 sec = 7.5 yds/sec 5 yards 2 sec = 2.5 yds/sec 1 2 4 3 7 8 5 6

10. When (time) do you think the 2 people are traveling the same speed? 32 • 0-2 seconds • 2-4 seconds • 4-6 seconds • 6-8 seconds 0 0 0 0 0 10 Countdown

11. Where (position) is each person when the two (2) people have the same speed? 32 • Sprinter and jogger at 30 yard line • Sprinter at 35 yd line; jogger at 40 yd line • Sprinter at 45 yard line; jogger at 50 yd line • Sprinter and jogger at 60 yd line • Sprinter at 75 yard line; jogger at 70 yd line 0 0 0 0 0 0 10 Countdown

12. Discussion (don’t copy this) Position vs. Time Speed vs. Time Money vs. Time B Speed (cm/sec) C Position (meters) Money ($) A Time (months) Section ASection BSection C Increasing _____ Decreasing _____ Increasing _____ Increasing _____ Decreasing _____ Increasing _____ Increasing _____ Decreasing _____ Increasing _____

13. About how much did my position change in each section? About how much did my speed change in each section? About how much did my money change in each section? Discussion (don’t copy this) Position vs. Time Speed vs. Time Money vs. Time B Speed (cm/sec) C Position (meters) Money ($) A Time (months) Section ASection BSection C +$10 -$5 +$15 • +5 cm/sec • -5 cm/sec +15 cm/sec +15 meters -15 meters +15 meters

14. Discussion (don’t copy this) Position vs. Time B C Position (meters) A Time (minutes) 10 20 30 Section ASection BSection C Speed = distance Time 15 meters 5 meters 10 meters 5 minutes 10 minutes 5 minutes = 3 meters minute = 0.5 meters minute = 2 meters minute