Question

kai was 200 meters north of the library when he remembered he had to return some books to the library. it took him 200 seconds to do the round trip. which best describes kais round - trip? his speed was 1 m/s, and his velocity was 0. his speed was 2 m/s, and his velocity was 0. his speed was 1 m/s, and his velocity was 1 m/s north. his speed was 2 m/s, and his velocity was 2 m/s south.

Explanation:

Step1: Calculate total distance

Kai goes 200 meters to the library and 200 meters back, so total distance $d = 200+200=400$ meters.

Step2: Calculate speed

Speed $v_{s}=\frac{d}{t}$, where $t = 200$ seconds. So $v_{s}=\frac{400}{200}=2$ m/s.

Step3: Calculate velocity

Velocity is displacement over time. Displacement is 0 (since he returns to the starting - point). So $v_{v}=\frac{\Delta x}{t}=\frac{0}{200}=0$ m/s.

Answer:

His speed was 2 m/s, and his velocity was 0.