Question

In a swimming pool of 50m track length, what will be the net displacement of the swimmer after completing a 250m race?

Answer 1

Hint: Given the length of the track in the question. Thus find the total distance in covering the swimming pool. Here we must also know what the difference between the displacement and distance is. Also when we travel some distance and return back to the initial point, then the net displacement will be zero, but the distance covered is not zero.

Complete answer:
Given that,
Track length of the swimming pool $=50m$
So, swimming forward and coming back, the swimmer will cover a total distance twice of the track length and that is 100m. Then the net displacement here is zero.
Then for the next round the swimmers cover a total distance of 200m and still the displacement is zero.
For the last 50m, the swimmer reaches the end of the pool.
So the displacement = length of the track =50m.

Note: Also remember that the distance is a scalar quantity where the displacement is a vector quantity. Then we can define the distance as the total path covered by an object. And the displacement is the shortest path covered by an object. Thus the displacement of an object can be zero, but the distance never comes to zero.