A swimmer swims 20 laps in a north-south facing pool in 7.00 minutes. Her first lap is toward the north. Her displacement and average velocity are
A) 0; 0.
B) 0; 2.38 m/s, south.
C) 0; 2.38 m/s, north.
D) 1 000 m, south; 2.38 m/s, south.
E) 1 000 m, north; 2.38 m/s, north.

Question

Quizplus · Accepted Answer

Displacement is a vector quantity that refers to the change in position of an object. Since the swimmer returns to the starting point after completing an even number of laps in a north-south facing pool, the overall change in position is zero, making the displacement 0. Average velocity is displacement divided by time. Since the displacement is 0, the average velocity is also 0, regardless of the distance swum or the time taken.

A Swimmer Swims 20 Laps in a North-South Facing Pool