1. SHMD 239 Kinesiology Unit 5

3. In the triathlon race, the time taken for the winner to complete the race was: Work out the average velocity for the different components of the triathlon. DistanceTime 1600 m Swim30 min 40 km Cycle90 min 10 km Run45 min

4. ANSWERS: Swim: Velocity = Displacement / Time 0m / 30 min 0km / 0.5 hr 0 km/hr

5. ANSWERS: Cycle: Velocity = Displacement / Time 40km / 90 min 0km / 1.5 hr 0 km/hr

6. ANSWERS: Run: Velocity = Displacement / Time 10km / 45 min 0.2km / 0.75 hr 0.27 km/hr

7. Dan & Gary were competing in a 800m race. Dan ran the first 400m of the race in 42 seconds and the second 400m in 58 seconds. Gary ran the first 400m in 52 seconds and the second 400m in 50 seconds. Answer the following questions?  Who won the race?  What was the speed of each competitor?  What was the velocity of each competitor?

8. ANSWERS: Who won the race? Dan won the race. Why? Dan: 400m = 42 sec 400m = 58 sec = 100 sec or 1.67 min Gary: 400m = 52 sec 400m = 50 sec = 102 sec or 1.7 min

9. ANSWERS: What was the speed of each competitor? Dan:Speed = Distance / Time = 800m / 100 sec = 8 m/sec Gary:Speed= Distance / Time = 800m / 102 sec = 7.84 m/sec

10. ANSWERS: What was the velocity of each competitor? Dan:Velocity = Displacement / Time = 0m / 100 sec = 0 m/sec Gary:Velocity = Displacement / Time = 0m / 102 sec = 0 m/sec

11. A swimmer covers the first 50m length of a 100m backstroke race at an average speed of 1.5m/s and the second length at an average speed of 1.2m/s.  What were the times for the first and second lengths, respectively?  What was the average speed for the whole race?  What was the average velocity for the whole race?

12. ANSWERS: What were the times for the first and second lengths? 1 st length: Speed= Distance / Time 1.5m/s= 50m / ? sec Time= Distance / Speed = 50m / 1.5m/s = 33.33 s

13. ANSWERS: What were the times for the first and second lengths? 2 nd length: Speed = Distance / Time 1.2m/s= 50m / ? sec Time= Distance / Speed = 50m / 1.2m/s = 41.67 s

14. ANSWERS: What was the average speed for the whole race? Speed= Distance / Time = 100m/(33.33s + 41.67s) = 100m/75s = 1.33 m/s

15. ANSWERS: What was the average velocity for the whole race? Velocity= Displacement / Time = 0m/(33.33s + 41.67s) = 0m/75s = 0 m/s

16.  Is a vector quantity that is measured by the rate at which velocity changes  An object is accelerating if it is changing its velocity  Decelerating is the opposite of accelerating - slowing down

17.  Acceleration = Change in Velocity / Time Taken  It can be worked out by finding: (vf – vi) t  Vf = final velocity  Vi = initial velocity  T = time interval  Units for acceleration = m/s²

18. QUESTION: A softball player sprints from 1 st base, to 2 nd base. If her instantaneous horizontal velocity is 9.3m/s when she is 8m from 2 nd base and 7.5m/s when she is 5m from 2 nd base 0.4s later. What is her acceleration over that 3m interval?

19. ANSWER: Acceleration = (vf – vi) t = (7.5 – 9.3) m/s 0.4 s = -1.8 m/s 0.4 s = -4.5 m/s