Final answer:
Distance is the total length of the path John takes from point A to B to C, while displacement is the straight-line distance from point A to point C. Distance measures how much ground is covered, and is a scalar quantity, whereas displacement includes direction and is a vector quantity.
Step-by-step explanation:
The distance John walks from point A to point B to point C is the total length of the path he takes. Displacement, on the other hand, is the straight-line distance from his starting point (point A) to his ending point (point C). To calculate the displacement, you would measure the length of a straight line from point A to point C irrespective of the path taken.
Distance is a scalar quantity that indicates how much ground has been covered during motion, whereas displacement is a vector quantity that not only indicates the length of the straight line between the starting and ending points but also includes direction. When discussing movement from one point to another, it's crucial to distinguish between these two concepts because while the distance can never be negative, displacement can be, depending on the direction of movement relative to the starting point.