Final answer:
James' average speed is 4 km/h and his average velocity is zero.
Step-by-step explanation:
To determine James' average speed, we can calculate the total distance he walks and divide it by the total time taken. James walks 2 km away from home and then walks back home along the same path, covering a total distance of 4 km. He takes 30 minutes for each leg of the trip, resulting in a total time of 60 minutes or 1 hour. Therefore, his average speed is 4 km / 1 hour = 4 km/h.
As for average velocity, it not only takes into account the distance but also the direction of motion. Since James walks away from home and then walks back along the same path, his displacement is zero. Displacement is the change in position, while distance is the total path covered. Therefore, James' average velocity is zero because there is no change in position despite walking a distance of 4 km.