Answer:
(i) The athlete's average speed for the whole journey is approximately 5.11 m/s.
(ii) Average velocity is a vector quantity that represents the displacement of an object divided by the total time taken to cover that displacement. It includes both magnitude (speed) and direction.
Average velocity = Total displacement / Total time taken
Average velocity = 432 meters / 219 seconds ≈ 1.97 m/s (rounded to two decimal places)
The athlete's average velocity for the whole journey is approximately 1.97 m/s.
Step-by-step explanation:
To calculate the athlete's average speed and average velocity for the whole journey, we need to consider the total displacement and the total time taken.
Let's break down the journey:
1. The athlete runs 775 meters due north in 148 seconds. The displacement in this case is +775 meters (positive because it's north), and the time taken is 148 seconds.
2. The athlete then runs 343 meters due south in 71 seconds. The displacement in this case is -343 meters (negative because it's south), and the time taken is 71 seconds.
To find the total displacement, we subtract the southward displacement from the northward displacement:
Total displacement = +775 meters - 343 meters = +432 meters
To find the total time taken, we add the times for each leg of the journey:
Total time taken = 148 seconds + 71 seconds = 219 seconds
Now, let's calculate the average speed:
Average speed = Total distance / Total time taken
Total distance = 775 meters + 343 meters = 1118 meters
Average speed = 1118 meters / 219 seconds ≈ 5.11 m/s (rounded to two decimal places)
Finally, let's calculate the average velocity:
Average velocity = Total displacement / Total time taken
Average velocity = 432 meters / 219 seconds ≈ 1.97 m/s (rounded to two decimal places)
So, the answers are:
(i) The athlete's average speed for the whole journey is approximately 5.11 m/s.
(ii) The athlete's average velocity for the whole journey is approximately 1.97 m/s.