Mr. smith is designing a race where velocity will be measured. which course would allow velocity to accurately get a winner?

a 5 mile course from the center of town heading north to the outskirts of town
a 100 meter swim in a 50 meter pool
a 2 mile run around a 400 meter track
a 10 mile bike course that zigzags through the mountains and back again

Velocity can be accurately measured in a 5 mile course from the center of town heading north to the outskirts of town.

Explanation: Velocity is defined as the rate of change of displacement.

Mathematically,

For last three parts, the displacement is coming out to be zero, because the final position of the object is equal to the initial position of the object. Hence, the velocity for these options cannot be measured.

For the first part, as the race track is in one direction only and the final position will be different from its initial position. So, the displacement will be non-zero. Hence, for this case velocity can be measured.