Question

(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?

Explanation:

Step1: Convert time to hours

2 hours 20 minutes = 2 + 20/60 = 2 + 1/3 = 7/3 hours

Step2: Calculate total distance for speed

Total distance = 115 + 85 = 200 km
Average speed = total distance/time = 200/(7/3) = 200×3/7 = 600/7 ≈ 85.71 km/h

Step3: Calculate displacement for velocity

Displacement = 115 - 85 = 30 km (east - west)
Average velocity = displacement/time = 30/(7/3) = 30×3/7 = 90/7 ≈ 12.86 km/h (east)

Answer:

Average speed: 85.71 km/h; Average velocity: 12.86 km/h (east)