(3) in a time of 2.5 minutes michael walks 150 m to the south and then turns around and walks 225 meters to…

(3) in a time of 2.5 minutes michael walks 150 m to the south and then turns around and walks 225 meters to the north. what are michael’s average speed and average velocity? (4) moreen drives her car 115 km to the east, turns around and then drives 85 km to the west. if this car trip takes her 2 hours and 20 minutes, what is her average speed and velocity?
Answer
Explanation:
Step1: Convert time to seconds for Michael's case
1 minute = 60 seconds, so 2.5 minutes = 2.5×60 = 150 s.
Step2: Calculate total distance for Michael
Total distance $d_{total - Michael}=150 + 225=375$ m.
Step3: Calculate average speed for Michael
Average speed $v_{avg - speed - Michael}=\frac{d_{total - Michael}}{t}$, so $v_{avg - speed - Michael}=\frac{375}{150}=2.5$ m/s.
Step4: Calculate displacement for Michael
Displacement $x_{Michael}=225 - 150 = 75$ m (north - direction is positive).
Step5: Calculate average velocity for Michael
Average velocity $v_{avg - velocity - Michael}=\frac{x_{Michael}}{t}=\frac{75}{150}=0.5$ m/s (north).
Step6: Convert time to hours for Moreen's case
2 hours 20 minutes = 2+\frac{20}{60}=2+\frac{1}{3}=\frac{7}{3}$ h.
Step7: Calculate total distance for Moreen
Total distance $d_{total - Moreen}=115 + 85 = 200$ km.
Step8: Calculate average speed for Moreen
Average speed $v_{avg - speed - Moreen}=\frac{d_{total - Moreen}}{t}=\frac{200}{\frac{7}{3}}=\frac{600}{7}\approx85.71$ km/h.
Step9: Calculate displacement for Moreen
Displacement $x_{Moreen}=115 - 85 = 30$ km (east - direction is positive).
Step10: Calculate average velocity for Moreen
Average velocity $v_{avg - velocity - Moreen}=\frac{x_{Moreen}}{t}=\frac{30}{\frac{7}{3}}=\frac{90}{7}\approx12.86$ km/h (east).
Answer:
Michael's average speed: 2.5 m/s Michael's average velocity: 0.5 m/s (north) Moreen's average speed: $\frac{600}{7}\approx85.71$ km/h Moreen's average velocity: $\frac{90}{7}\approx12.86$ km/h (east)