Question 7
A child travels 60 m from A to B along a straight path. Then, instead of going on, they come back 40 m. What are the distance travelled and the displacement, in that order?
The right answer is the one marked above.
Distance 100 m, displacement 20 m. The return leg points the opposite way to the first, so that 40 m is taken as negative:
total displacement = 60 m + (−40 m) = 20 m
Distance, though, has no sign. The distance travelled is 60 + 40 = 100 m — the return leg adds on. Distance never decreases; displacement can decrease, can be zero, and can even be negative.