Question

1. swimming one lap in a pool is defined as going across a pool and back again. if a swimmer swims 3 laps in 9 minutes, how can his average velocity be zero? a. his average velocity is zero because his total distance is zero. b. his average velocity is zero because his total displacement is zero. c. his average velocity is zero because the number of laps completed is an odd number. d. his average velocity is zero because the velocity of each successive lap is equal and opposite.

Explanation:

Average velocity is displacement divided by time. After swimming 3 laps (going across and back each lap), the swimmer returns to the starting - point. So, the total displacement is zero. Since average velocity = $\frac{\text{displacement}}{\text{time}}$ and displacement is zero, average velocity is zero.

Answer:

B. His average velocity is zero because his total displacement is zero.